The Atomic Bomb and the End of World War II

A Collection of Primary Sources

Updated National Security Archive Posting Marks 70th Anniversary of the Atomic Bombings of Japan and the End of World War II

Extensive Compilation of Primary Source Documents Explores Manhattan Project, Petitions Against Military Use of Atomic Weapons, Debates over Japanese Surrender Terms, Atomic Targeting Decisions, and Lagging Awareness of Radiation Effects

New Information Spotlights General Dwight D. Eisenhower’s Early Misgivings about First Nuclear Use

General Curtis Lemay's Report on the Firebombing of Tokyo, March 1945

 

National Security Archive Electronic Briefing Book No. 525

Edited by William Burr

Originally posted - August 5, 2005
First updated - April 27, 2007
Latest update - August 4, 2015

For more information, contact:
William Burr – 202 / 994-7000 or nsarchiv@gwu.edu

Nagasaki, August 10, 1945; photograph by Yosuke Yamahata; used with permission of copyright holder, Shogo Yamahata/Courtesy: IDG films. Photo restoration by TX Unlimited, San Francisco

August 4, 2015- A few months after the atomic bombings of Hiroshima and Nagasaki, General Dwight D. Eisenhower commented during a social occasion “how he had hoped that the war might have ended without our having to use the atomic bomb.” This virtually unknown evidence from the diary of Robert P. Meiklejohn, an assistant to Ambassador W. Averell Harriman, published for the first time today by the National Security Archive, confirms that the future President Eisenhower had early misgivings about the first use of atomic weapons by the United States. General George C. Marshall is the only high-level official whose contemporaneous (pre-Hiroshima) doubts about using the weapons against cities are on record.

On the 70th anniversary of the bombing of Hiroshima on August 6, 1945, the National Security Archive updates its 2005 publication of the most comprehensive on-line collection of declassified U.S. government documents on the first use of the atomic bomb and the end of the war in the Pacific. This update presents previously unpublished material and translations of difficult-to-find records. Included are documents on the early stages of the U.S. atomic bomb project, Army Air Force General Curtis LeMay’s report on the firebombing of Tokyo (March 1945), Secretary of War Henry Stimson’s requests for modification of unconditional surrender terms, Soviet documents relating to the events, excerpts from the Robert P. Meiklejohn diaries mentioned above, and selections from the diaries of Walter J. Brown, special assistant to Secretary of State James Byrnes.

The original 2005 posting included a wide range of material, including formerly top secret "Magic" summaries of intercepted Japanese communications and the first-ever full translations from the Japanese of accounts of high level meetings and discussions in Tokyo leading to the Emperor’s decision to surrender. Also documented are U.S. decisions to target Japanese cities, pre-Hiroshima petitions by scientists questioning the military use of the A-bomb, proposals for demonstrating the effects of the bomb, debates over whether to modify unconditional surrender terms, reports from the bombing missions of Hiroshima and Nagasaki, and belated top-level awareness of the radiation effects of atomic weapons.

The documents can help readers to make up their own minds about long-standing controversies such as whether the first use of atomic weapons was justified, whether President Harry S. Truman had alternatives to atomic attacks for ending the war, and what the impact of the Soviet declaration of war on Japan was. Since the 1960s, when the declassification of important sources began, historians have engaged in vigorous debate over the bomb and the end of World War II. Drawing on sources at the National Archives and the Library of Congress as well as Japanese materials, this electronic briefing book includes key documents that historians of the events have relied upon to present their findings and advance their interpretations.

The Atomic Bomb and the End of World War II: A Collection of Primary Sources

A nuclear weapon of the "Little Boy" type, the uranium gun-type detonated over Hiroshima. It is 28 inches in diameter and 120 inches long. "Little Boy" weighed about 9,000 pounds and had a yield approximating 15,000 tons of high explosives. (Copy from U.S. National Archives, RG 77-AEC)

Seventy years ago this month, the United States dropped atomic bombs on Hiroshima and Nagasaki, the Soviet Union declared war on Japan, and the Japanese government surrendered to the United States and its allies. The nuclear age had truly begun with the first military use of atomic weapons. With the material that follows, the National Security Archive publishes the most comprehensive on-line collection to date of declassified U.S. government documents on the atomic bomb and the end of the war in the Pacific. Besides material from the files of the Manhattan Project, this collection includes formerly “Top Secret Ultra” summaries and translations of Japanese diplomatic cable traffic intercepted under the “Magic” program. Moreover, the collection includes for the first time translations from Japanese sources of high level meetings and discussions in Tokyo, including the conferences when Emperor Hirohito authorized the final decision to surrender.[1]

A nuclear weapon of the "Fat Man" type, the plutonium implosion type detonated over Nagasaki. 60 inches in diameter and 128 inches long, the weapon weighed about 10,000 pounds and had a yield approximating 21,000 tons of high explosives (Copy from U.S. National Archives, RG 77-AEC)

Ever since the atomic bombs were exploded over Japanese cities, historians, social scientists, journalists, World War II veterans, and ordinary citizens have engaged in intense controversy about the events of August 1945. John Hersey’s Hiroshima, first published in the New Yorker in 1946 encouraged unsettled readers to question the bombings while church groups and some commentators, most prominently Norman Cousins, explicitly criticized them. Former Secretary of War Henry Stimson found the criticisms troubling and published an influential justification for the attacks in Harper’s.[2] During the 1960s the availability of primary sources made historical research and writing possible and the debate became more vigorous. Historians Herbert Feis and Gar Alperovitz raised searching questions about the first use of nuclear weapons and their broader political and diplomatic implications. The controversy, especially the arguments made by Alperovitz and others about “atomic diplomacy” quickly became caught up in heated debates over Cold War “revisionism.” The controversy simmered over the years with major contributions by Martin Sherwin and Barton J. Bernstein but it became explosive during the mid-1990s when curators at the National Air and Space Museum met the wrath of the Air Force Association over a proposed historical exhibit on the Enola Gay.[3] The NASM exhibit was drastically scaled-down but historians and journalist continued to engage in the debate. Alperovitz, Bernstein, and Sherwin made new contributions as did other historians, social scientists, and journalists including Richard B. Frank, Herbert Bix, Sadao Asada, Kai Bird, Robert James Maddox, Sean Malloy, Robert P. Newman, Robert S. Norris, Tsuyoshi Hagesawa, and J. Samuel Walker.[4]

Taken at Tinian Island on the afternoon of August 5, 1945, this shows the tail of the Enola Gay being edged over the pit and into position to load "Little Boy" into the bomb bay. The weapon is in the pit covered with canvas. Various personnel and guards are standing around the loading area. (Photo from U.S. National Archives, RG 77-BT)

The continued controversy has revolved around the following, among other, questions:

  • were the atomic strikes necessary primarily to avert an invasion of Japan in November 1945?
  • Did Truman authorize the use of atomic bombs for diplomatic-political reasons-- to intimidate the Soviets--or was his major goal to force Japan to surrender and bring the war to an early end?
  • If ending the war quickly was the most important motivation of Truman and his advisers to what extent did they see an “atomic diplomacy” capability as a “bonus”?
  • To what extent did subsequent justification for the atomic bomb exaggerate or misuse wartime estimates for U.S. casualties stemming from an invasion of Japan?
  • Were there alternatives to the use of the weapons? If there were, what were they and how plausible are they in retrospect? Why were alternatives not pursued?
  • How did the U.S. government plan to use the bombs? What concepts did war planners use to select targets? To what extent were senior officials interested in looking at alternatives to urban targets? How familiar was President Truman with the concepts that led target planners chose major cities as targets?
  • What did senior officials know about the effects of atomic bombs before they were first used. How much did top officials know about the radiation effects of the weapons?
  • Did President Truman make a decision, in a robust sense, to use the bomb or did he inherit a decision that had already been made?
  • Were the Japanese ready to surrender before the bombs were dropped? To what extent had Emperor Hirohito prolonged the war unnecessarily by not seizing opportunities for surrender?
  • If the United States had been more flexible about the demand for “unconditional surrender” by explicitly or implicitly guaranteeing a constitutional monarchy would Japan have surrendered earlier than it did?
  • How decisive was the atomic bombings to the Japanese decision to surrender?
  • Was the bombing of Nagasaki unnecessary? To the extent that the atomic bombing was critically important to the Japanese decision to surrender would it have been enough to destroy one city?
  • Would the Soviet declaration of war have been enough to compel Tokyo to admit defeat?
  • Was the dropping of the atomic bombs morally justifiable?
This shows the "Little Boy" weapon in the pit ready for loading into the bomb bay of the Enola Gay. (Photo from U.S. National Archives, RG 77-BT)

This compilation will not attempt to answer these questions or use primary sources to stake out positions on any of them. Nor is it an attempt to substitute for the extraordinary rich literature on the atomic bombings and the end of World War II. Nor does it include any of the interviews, documents prepared after the events, and post-World War II correspondence, etc. that participants in the debate have brought to bear in framing their arguments. Originally this collection did not include documents on the origins and development of the Manhattan Project, although this updated posting includes some significant records for context. By providing access to a broad range of U.S. and Japanese documents, mainly from the spring and summer of 1945, interested readers can see for themselves the crucial source material that scholars have used to shape narrative accounts of the historical developments and to frame their arguments about the questions that have provoked controversy over the years. To help readers who are less familiar with the debates, commentary on some of the documents will point out, although far from comprehensively, some of the ways in which they have been interpreted. With direct access to the documents, readers may develop their own answers to the questions raised above. The documents may even provoke new questions.

Contributors to the historical controversy have deployed the documents selected here to support their arguments about the first use of nuclear weapons and the end of World War II. The editor has closely reviewed the footnotes and endnotes in a variety of articles and books and selected documents cited by participants on the various sides of the controversy.[5] While the editor has a point of view on the issues, to the greatest extent possible he has tried to not let that influence document selection, e.g., by selectively withholding or including documents that may buttress one point of view or the other. The task of compilation involved consultation of primary sources at the National Archives, mainly in Manhattan Project files held in the records of the Army Corps of Engineers, Record Group 77, but also in the archival records of the National Security Agency. Private collections were also important, such as the Henry L. Stimson Papers held at Yale University (although available on microfilm, for example, at the Library of Congress) and the papers of W. Averell Harriman at the Library of Congress. To a great extent the documents selected for this compilation have been declassified for years, even decades; the most recent declassifications were in the 1990s.

This shows "Little Boy" being raised for loading into the Enola Gay's bomb bay. (Photo from U.S. National Archives, RG 77-BT)

The U.S. documents cited here will be familiar to many knowledgeable readers on the Hiroshima-Nagasaki controversy and the history of the Manhattan Project. To provide a fuller picture of the transition from U.S.-Japanese antagonism to reconciliation, the editor has done what could be done within time and resource constraints to present information on the activities and points of view of Japanese policymakers and diplomats. This includes a number of formerly top secret summaries of intercepted Japanese diplomatic communications, which enable interested readers to form their own judgments about the direction of Japanese diplomacy in the weeks before the atomic bombings. Moreover, to shed light on the considerations that induced Japan’s surrender, this briefing book includes new translations of Japanese primary sources on crucial events, including accounts of the conferences on August 9 and 14, where Emperor Hirohito made decisions to accept Allied terms of surrender.

[Editor’s Note: Originally prepared in July 2005 this posting has been updated, with new documents, changes in organization, and other editorial changes. As noted, some documents relating to the origins of the Manhattan Project have been included in addition to entries from the Robert P. Meiklejohn diaries and translations of a few Soviet documents, among other items. Moreover, recent significant contributions to the scholarly literature have been taken into account.]

Table of Contents for the Documents

I. Background on the U. S. Atomic Project

II. Targeting Japan

III. Debates on Alternatives to First Use and Unconditional Surrender

IV. The Japanese Search for Soviet Mediation

V. The Trinity Test

VI. The Potsdam Conference

VII. Debates among the Japanese – Late July/Early August 1945

VIII. The Execution Order

IX. The First Nuclear Strikes and their Impact

X. Toward Surrender

XI. Confronting the Problem of Radiation Poisoning

XII. Eisenhower and McCloy’s Views on the Bombings and Atomic Weapons

I. Background on the U.S. Atomic Project

Documents 1A-C: Report of the Uranium Committee

1A. Arthur H. Compton, National Academy of Sciences Committee on Atomic Fission, to Frank Jewett, President, National Academy of Sciences, 17 May 1941, Secret

1B. Report to the President of the National Academy of Sciences by the Academy Committee on Uranium, 6 November 1941, Secret

1C. Vannevar Bush, Director, Office of Scientific Research and Development, to President Roosevelt, 27 November 1941, Secret

Source: National Archives, Records of the Office of Scientific Research and Development, Record Group 227 (hereinafter RG 227), Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section A (1940-1941)."

The mushroom cloud billowing up 20,000 feet over Hiroshima on the morning of August 6, 1945 (Photo from U.S. National Archives, RG 77-AEC)

This set of documents concerns the work of the Uranium Committee of the National Academy of Sciences, an exploratory project that was the lead-up to the actual production effort undertaken by the Manhattan Project. The initial report, May 1941, showed how leading American scientists grappled with the potential of nuclear energy for military purposes. At the outset, three possibilities were envisioned: radiological warfare, a power source for submarines and ships, and explosives. To produce material for any of those purposes required a capability to separate uranium isotopes in order to produce fissionable U-235. Also necessary for those capabilities was the production of a nuclear chain reaction. At the time of the first report, various methods for producing a chain reaction were envisioned and money was being budgeted to try them out.

Later that year, the Uranium Committee completed its report and OSRD Chairman Vannevar Bush reported the findings to President Roosevelt: As Bush emphasized, the U.S. findings were more conservative than those in the British MAUD report: the bomb would be somewhat “less effective,” would take longer to produce, and at a higher cost. One of the report’s key findings was that a fission bomb of superlatively destructive power will result from bringing quickly together a sufficient mass of element U235.” That was a certainty, “as sure as any untried prediction based upon theory and experiment can be.” The critically important task was to develop ways and means to separate highly enriched uranium from uranium-238. To get production going, Bush wanted to establish a “carefully chosen engineering group to study plans for possible production.” This was the basis of the Top Policy Group, or the S-1 Committee, which Bush and James B. Conant quickly established.[6]

In its discussion of the effects of an atomic weapon, the committee considered both blast and radiological damage. With respect to the latter, “It is possible that the destructive effects on life caused by the intense radioactivity of the products of the explosion may be as important as those of the explosion itself.” This insight was overlooked when top officials of the Manhattan Project considered the targeting of Japan during 1945.[7]

Documents 2A-B: Going Ahead with the Bomb

2A: Vannevar Bush to President Roosevelt, 9 March 1942, with memo from Roosevelt attached, 11 March 1942, Secret

2B: Vannevar Bush to President Roosevelt, 16 December 1942, Secret (report not attached)

Sources: 2A: RG 227, Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section II (1941-1942): 2B: Bush-Conant papers, S-1 Historical File, Reports to and Conferences with the President (1942-1944)

The Enola Gay returns to Tinian Island after the strike on Hiroshima. (Photo from U.S. National Archives, RG 77-BT)

The Manhattan Project never had an official charter establishing it and defining its mission, but these two documents are the functional equivalent of a charter, in terms of presidential approvals for the mission, not to mention for a huge budget. In a progress report, Bush told President Roosevelt that the bomb project was on a pilot plant basis, but not yet at the production stage. By the summer, once “production plants” would be at work, he proposed that the War Department take over the project. In reply, Roosevelt wrote a short memo endorsing Bush’s ideas as long as absolute secrecy could be maintained. According to Robert S. Norris, this was “the fateful decision” to turn over the atomic project to military control.[8]

Some months later, with the Manhattan Project already underway and under the direction of General Leslie Grove, Bush outlined to Roosevelt the effort necessary to produce six fission bombs. With the goal of having enough fissile material by the first half of 1945 to produce the bombs, Bush was worried that the Germans might get there first. Thus, he wanted Roosevelt’s instructions as to whether the project should be “vigorously pushed throughout.” Unlike the pilot plant proposal described above, Bush described a real production order for the bomb, at an estimated cost of a “serious figure”: $400 million, which was an optimistic projection given the eventual cost of $1.9 billion. To keep the secret, Bush wanted to avoid a “ruinous” appropriations request to Congress and asked Roosevelt to ask Congress for the necessary discretionary funds. Initialed by President Roosevelt (“VB OK FDR”), this may have been the closest that he came to a formal approval of the Manhattan Project.

Document 3: Memorandum by Leslie R. Grove, “Policy Meeting, 5/5/43,” Top Secret

Source: National Archives, Record Group 77, Records of the Army Corps of Engineers (hereinafter RG 77), Manhattan Engineering District (MED), Minutes of the Military Policy Meeting (5 May 1943), Correspondence (“Top Secret”) of the Manhattan Engineer District, 1942-1946, microfilm publication M1109 (Washington, D.C.: National Archives and Records Administration, 1980), Roll 3, Target 6, Folder 23, “Military Policy Committee, Minutes of Meetings”

Before the Manhattan Project had produced any weapons, senior U.S. government officials had Japanese targets in mind. Besides discussing programmatic matters (e.g., status of gaseous diffusion plants, heavy water production for reactors, and staffing at Las Alamos), the participants agreed that the first use could be Japanese naval forces concentrated at Truk Harbor, an atoll in the Caroline Islands. If there was a misfire the weapon would be difficult for the Japanese to recover, which would not be the case if Tokyo was targeted. Targeting Germany was rejected because the Germans were considered more likely to “secure knowledge” from a defective weapon than the Japanese. That is, the United States could possibly be in danger if the Nazis acquired more knowledge about how to build a bomb.[9]

Document 4: Memo from General Groves to the Chief of Staff [Marshall], “Atomic Fission Bombs – Present Status and Expected Progress,” 7 August 1944, Top Secret, excised copy

Source: RG 77, Correspondence ("Top Secret") of the Manhattan Engineer District, 1942-1946, file 25M

A "Fat Man" test unit being raised from the pit into the bomb bay of a B-29 for bombing practice during the weeks before the attack on Nagasaki. (Photo from U.S. National Archives, RG 77-BT)

This memorandum from General Groves to General Marshall captured how far the Manhattan Project had come in less than two years since Bush’s December 1942 report to President Roosevelt. Groves did not mention this but around the time he wrote this the Manhattan Project had working at its far-flung installations over 125,000 people ; taking into account high labor turnover some 485,000 people worked on the project (1 out of every 250 people in the country at that time). What these people were laboring to construct, directly or indirectly, were two types of weapons—a gun-type weapon using U-235 and an implosion weapon using plutonium (although the possibility of U-235 was also under consideration). As the scientists had learned, a gun-type weapon based on plutonium was “impossible” because that element had an “unexpected property”: spontaneous neutron emissions would cause the weapon to “fizzle.”[10] For both the gun-type and the implosion weapons, a production schedule had been established and both would be available during 1945. The discussion of weapons effects centered on blast damage models; radiation and other effects were overlooked.

Document 5: Memorandum from Vannevar Bush and James B. Conant, Office of Scientific Research and Development, to Secretary of War, September 30, 1944, Top Secret

Source: RG 77, Harrison-Bundy Files (H-B Files), folder 69 (copy from microfilm)

While Groves worried about the engineering and production problems, key War Department advisers were becoming troubled over the diplomatic and political implications of these enormously powerful weapons and the dangers of a global nuclear arms race. Concerned that President Roosevelt had an overly “cavalier” belief about the possibility of maintaining a post-war Anglo-American atomic monopoly, Bush and Conant recognized the limits of secrecy and wanted to disabuse senior officials of the notion that an atomic monopoly was possible. To suggest alternatives, they drafted this memorandum about the importance of the international exchange of information and international inspection to stem dangerous nuclear competition.[11]

Documents 6A-D: President Truman Learns the Secret:

6A: Memorandum for the Secretary of War from General L. R. Groves, “Atomic Fission Bombs,” April 23, 1945

6B: Memorandum discussed with the President, April 25, 1945

6C: [Untitled memorandum by General L.R. Groves, April 25, 1945

6D: Diary Entry, April 25, 1945

Sources: A: RG 77, Commanding General’s file no. 24, tab D; B: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress); C: Source: Record Group 200, Papers of General Leslie R. Groves, Correspondence 1941-1970, box 3, “F”; D: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

A photo prepared by U.S. Air Intelligence for analytical work on the destructiveness of atomic weapons. The total area devastated by the atomic strike on Hiroshima is shown in the darkened area (within the circle) of the photo. The numbered items are military and industrial installations with the percentages of total destruction. (Click on photo to enlarge.)
(Photo from U.S. National Archives, RG 77-AEC)

Soon after he was sworn in as president following President Roosevelt’s death, Harry Truman learned about the top secret Manhattan Project from a briefing from Secretary of War Stimson and Manhattan Project chief General Groves, who went through the “back door” to escape the watchful press. Stimson, who later wrote up the meeting in his diary, also prepared a discussion paper, which raised broader policy issues associated with the imminent possession of “the most terrible weapon ever known in human history.” In a background report prepared for the meeting, Groves provided a detailed overview of the bomb project from the raw materials to processing nuclear fuel to assembling the weapons to plans for using them, which were starting to crystallize.

With respect to the point about assembling the weapons, the first gun-type weapon “should be ready about 1 August 1945” while an implosion weapon would also be available that month. “The target is and was always expected to be Japan.” The question whether Truman “inherited assumptions” from the Roosevelt administration that that the bomb would be used has been a controversial one. Alperovitz and Sherwin have argued that Truman made “a real decision” to use the bomb on Japan by choosing “between various forms of diplomacy and warfare.” In contrast, Bernstein found that Truman “never questioned [the] assumption” that the bomb would and should be used. Norris also noted that “Truman’s `decision’ was a decision not to override previous plans to use the bomb.”[12]

II. Targeting Japan

Document 7: Commander F. L. Ashworth to Major General L.R. Groves, “The Base of Operations of the 509th Composite Group,” February 24, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5g

The force of B-29 nuclear delivery vehicles that was being readied for first nuclear use—the Army Air Force’s 509th Composite Group—required an operational base in the Western Pacific. In late February 1945, months before atomic bombs were ready for use, the high command selected Tinian, an island in the Northern Marianas Islands, for that base.

Document 8: Headquarters XXI Bomber Command, “Tactical Mission Report, Mission No. 40 Flown 10 March 1945,”n.d., Secret

Source: Library of Congress, Curtis LeMay Papers, Box B-36

As part of the war with Japan, the Army Air Force waged a campaign to destroy major industrial centers with incendiary bombs. This document is General Curtis LeMay’s report on the firebombing of Tokyo--“the most destructive air raid in history”--which burned down over 16 square miles of the city, killed up to 100,00 civilians (the official figure was 83,793), injured more than 40,000, and made over 1 million homeless. [13] According to the “Foreword,” the purpose of the raid, which dropped 1,665 tons of incendiary bombs, was to destroy industrial and strategic targets “not to bomb indiscriminately civilian populations.” Air Force planners, however, did not distinguish civilian workers from the industrial and strategic structures that they were trying to destroy.

The killing of workers in the urban-industrial sector was one of the explicit goals of the air campaign against Japanese cities. According to a Joint Chiefs of Staff report on Japanese target systems, expected results from the bombing campaign included: “The absorption of man-hours in repair and relief; the dislocation of labor by casualty; the interruption of public services necessary to production, and above all the destruction of factories engaged in war industry.” While Stimson would later raise questions about the bombing of Japanese cities, he was largely disengaged from the details (as he was with atomic targeting).[14]

Firebombing raids on other cities followed Tokyo, including Osaka, Kobe, Yokahama, and Nagoya, but with fewer casualties (many civilians had fled the cities). For some historians, the urban fire-bombing strategy facilitated atomic targeting by creating a “new moral context,” in which earlier proscriptions against intentional targeting of civilians had eroded.[15]

Document 9: Notes on Initial Meeting of Target Committee, May 2, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5d (copy from microfilm)

On 27 April, military officers and nuclear scientists met to discuss bombing techniques, criteria for target selection, and overall mission requirements. The discussion of “available targets” included Hiroshima, the “largest untouched target not on the 21st Bomber Command priority list.” But other targets were under consideration, including Yawata (northern Kyushu), Yokohama, and Tokyo (even though it was practically “rubble.”) The problem was that the Air Force had a policy of “laying waste” to Japan’s cities which created tension with the objective of reserving some urban targets for nuclear destruction. [16]

Document 10: Memorandum from J. R. Oppenheimer to Brigadier General Farrell, May 11, 1945

Source: RG 77, MED Records, Top Secret Documents, File no. 5g (copy from microfilm)

The polar cap of the "Fat Man" weapon being sprayed with plastic spray paint in front of Assembly Building Number 2. (Photo from U.S. National Archives, RG 77-BT)

As director of Los Alamos Laboratory, Oppenheimer’s priority was producing a deliverable bomb, but not so much the effects of the weapon on the people at the target. In keeping with General Groves’ emphasis on compartmentalization, the Manhattan Project experts on the effects of radiation on human biology were at the MetLab and other offices and had no interaction with the production and targeting units. In this short memorandum to Groves’ deputy, General Farrell, Oppenheimer explained the need for precautions because of the radiological dangers of a nuclear detonation. The initial radiation from the detonation would be fatal within a radius of about 6/10ths of a mile and “injurious” within a radius of a mile. The point was to keep the bombing mission crew safe; concern about radiation effects had no impact on targeting decisions. [17]

Document 11: Memorandum from Major J. A. Derry and Dr. N.F. Ramsey to General L.R. Groves, “Summary of Target Committee Meetings on 10 and 11 May 1945,” May 12, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5d (copy from microfilm)

Scientists and officers held further discussion of bombing mission requirements, including height of detonation, weather, radiation effects (Oppenheimer’s memo), plans for possible mission abort, and the various aspects of target selection, including priority cities (“a large urban area of more than three miles diameter”) and psychological dimension. As for target cities, the committee agreed that the following should be exempt from Army Air Force bombing so they would be available for nuclear targeting: Kyoto, Hiroshima, Yokohama, and Kokura Arsenal. Japan’s cultural capital, Kyoto, would not stay on the list. Pressure from Secretary of War Stimson had already taken Kyoto off the list of targets for incendiary bombings and he would successfully object to the atomic bombing of that city. [18]

Document 12: Stimson Diary Entries, May 14 and 15, 1945

Source: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

On May 14 and 15, Stimson had several conversations involving S-1 (the atomic bomb); during a talk with Assistant Secretary of War John J. McCloy, he estimated that possession of the bomb gave Washington a tremendous advantage—“held all the cards,” a “royal straight flush”-- in dealing with Moscow on post-war problems: “They can’t get along without our help and industries and we have coming into action a weapon which will be unique.” The next day a discussion of divergences with Moscow over the Far East made Stimson wonder whether the atomic bomb would be ready when Truman met with Stalin in July. If it was, he believed that the bomb would be the “master card” in U.S. diplomacy. This and other entries from the Stimson diary (as well as the entry from the Davies diary that follows) are important to arguments developed by Gar Alperovitz and Barton J. Bernstein, among others, although with significantly different emphases, that in light of controversies with the Soviet Union over Eastern Europe and other areas, top officials in the Truman administration believed that possessing the atomic bomb would provide them with significant leverage for inducing Moscow’s acquiescence in U.S. objectives.[19]

Document 13: Davies Diary entry for May 21, 1945

Source: Joseph E. Davies Papers, Library of Congress, box 17, 21 May 1945

While officials at the Pentagon continued to look closely at the problem of atomic targets, President Truman, like Stimson, was thinking about the diplomatic implications of the bomb. During a conversation with Joseph E. Davies, a prominent Washington lawyer and former ambassador to the Soviet Union, Truman said that he wanted to delay talks with Stalin and Churchill until July when the first atomic device had been tested. Alperovitz treated this entry as evidence in support of the atomic diplomacy argument, but other historians, ranging from Robert Maddox to Gabriel Kolko, have denied that the timing of the Potsdam conference had anything to do with the goal of using the bomb to intimidate the Soviets.[20]

Document 14: Letter, O. C. Brewster to President Truman, 24 May 1945, with note from Stimson to Marshall, 30 May 1945, attached, secret

Source: Harrison-Bundy Files relating to the Development of the Atomic Bomb, 1942-1946, microfilm publication M1108 (Washington, D.C.: National Archives and Records Administration, 1980), File 77: "Interim Committee - International Control."

In what Stimson called the “letter of an honest man,” Oswald C. Brewster sent President Truman a profound analysis of the danger and unfeasibility of a U.S. atomic monopoly. [21] An engineer for the Kellex Corporation, which was involved in the gas diffusion project to enrich uranium, Brewster recognized that the objective was fissile material for a weapon. That goal, he feared, raised terrifying prospects with implications for the “inevitable destruction of our present day civilization.” Once the U.S. had used the bomb in combat other great powers would not tolerate a monopoly by any nation and the sole possessor would be “be the most hated and feared nation on earth.” Even the U.S.’s closest allies would want the bomb because “how could they know where our friendship might be five, ten, or twenty years hence.” Nuclear proliferation and arms races would be certain unless the U.S. worked toward international supervision and inspection of nuclear plants.

Brewster suggested that Japan could be used as a “target” for a “demonstration” of the bomb, which he did not further define. His implicit preference, however, was for non-use; he wrote that it would be better to take U.S. casualties in “conquering Japan” than “to bring upon the world the tragedy of unrestrained competitive production of this material.”

Document 15: Minutes of Third Target Committee Meeting – Washington, May 28, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5d (copy from microfilm)

More updates on training missions, target selection, and conditions required for successful detonation over the target. The target would be a city--either Hiroshima, Kyoto (still on the list), or Niigata--but specific “aiming points” would not be specified at that time nor would industrial “pin point” targets because they were likely to be on the “fringes” a city. The bomb would be dropped in the city’s center. “Pumpkins” referred to bright orange, pumpkin-shaped high explosive bombs—shaped like the “Fat Man” implosion weapon--used for bombing run test missions.

Document 16: General Lauris Norstad to Commanding General, XXI Bomber Command, “509th Composite Group; Special Functions,” May 29, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5g (copy from microfilm)

The 509th Composite Group’s cover story for its secret mission was the preparation of “Pumpkins” for use in battle. In this memorandum, Norstad reviewed the complex requirements for preparing B-29s and their crew for successful nuclear strikes.

Document 17: Assistant Secretary of War John J. McCloy, “Memorandum of Conversation with General Marshal May 29, 1945 – 11:45 p.m.,” Top Secret

Source: Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 12, S-1

Tacitly dissenting from the Targeting Committee’s recommendations, Army Chief of Staff George Marshall argued for initial nuclear use against a clear-cut military target such as a “large naval installation.” If that did not work, manufacturing areas could be targeted, but only after warning their inhabitants. Marshall noted the “opprobrium which might follow from an ill considered employment of such force.” This document has played a role in arguments developed by Barton J. Bernstein that figures such as Marshall and Stimson were “caught between an older morality that opposed the intentional killing of noncombatants and a newer one that stressed virtually total war.”[22]

Document 18: “Notes of the Interim Committee Meeting Thursday, 31 May 1945, 10:00 A.M. to 1:15 P.M. – 2:15 P.M. to 4:15 P.M., ” n.d., Top Secret

Source: RG 77, MED Records, H-B files, folder no. 100 (copy from microfilm)

With Secretary of War Stimson presiding, members of the committee heard reports on a variety of Manhattan Project issues, including the stages of development of the atomic project, problems of secrecy, the possibility of informing the Soviet Union, cooperation with “like-minded” powers, the military impact of the bomb on Japan, and the problem of “undesirable scientists.” Interested in producing the “greatest psychological effect,” the Committee members agreed that the “most desirable target would be a vital war plant employing a large number of workers and closely surrounded by workers’ houses.” Exactly how the mass deaths of civilians would persuade Japanese rulers to surrender was not discussed. Bernstein has argued that this target choice represented an uneasy endorsement of “terror bombing”--the target was not exclusively military or civilian; nevertheless, worker’s housing would include non-combatant men, women, and children.[23]

Document 19: General George A. Lincoln to General Hull, June 4, 1945, enclosing draft, Top Secret

Source: Record Group 165, Records of the War Department General and Special Staffs, American-British-Canadian Top Secret Correspondence, Box 504, “ABC 387 Japan (15 Feb. 45)

Ground view of Nagasaki before and after the bombing; radiuses in increments of 1,000 feet from Ground Zero are shown. (Photo from U.S. National Archives, RG 77-MDH)

George A. Lincoln, chief of the Strategy and Policy Group at U.S. Army’s Operations Department, commented on a memorandum by former President Herbert Hoover that Stimson had passed on for analysis. Hoover proposed a compromise solution with Japan that would allow Tokyo to retain part of its empire in East Asia (including Korea and Japan) as a way to head off Soviet influence in the region. While Lincoln believed that the proposed peace teams were militarily acceptable he doubted that they were workable or that they could check Soviet “expansion” which he saw as an inescapable result of World War II. As to how the war with Japan would end, he saw it as “unpredictable,” but speculated that “it will take Russian entry into the war, combined with a landing, or imminent threat of a landing, on Japan proper by us, to convince them of the hopelessness of their situation.” Lincoln derided Hoover’s casualty estimate of 500,000. J. Samuel Walker has cited this document to make the point that “contrary to revisionist assertions, American policymakers in the summer of 1945 were far from certain that the Soviet invasion of Manchuria would be enough in itself to force a Japanese surrender.” [24]

Document 20: Memorandum from R. Gordon Arneson, Interim Committee Secretary, to Mr. Harrison, June 6, 1945, Top Secret

Source: RG 77, MED Records, H-B files, folder no. 100 (copy from microfilm)

In a memorandum to George Harrison, Stimson’s special assistant on Manhattan Project matters, Arneson noted actions taken at the recent Interim Committee meetings, including target criterion and an attack “without prior warning.”

Document 21: Memorandum of Conference with the President, June 6, 1945, Top Secret

Source: Henry Stimson Papers, Sterling Library, Yale University (microfilm at Library of Congress)

Stimson and Truman began this meeting by discussing how they should handle a conflict with French President DeGaulle over the movement by French forces into Italian territory. (Truman finally cut off military aid to France to compel the French to pull back). [25] As evident from the discussion, Stimson strongly disliked de Gaulle whom he regarded as “psychopathic.” The conversation soon turned to the atomic bomb, with some discussion about plans to inform the Soviets but only after a successful test. Both agreed that the possibility of a nuclear “partnership” with Moscow would depend on “quid pro quos”: “the settlement of the Polish, Rumanian, Yugoslavian, and Manchurian problems.” At the end, Stimson shared his doubts about targeting cities and killing civilians through area bombing because of its impact on the U.S.’s reputation as well as on the problem of finding targets for the atomic bomb. Barton Bernstein has also pointed to this as additional evidence of the influence on Stimson of an “an older morality.”

III. Debates on Alternatives to First Use and Unconditional Surrender

Document 22: Memorandum from Arthur B. Compton to the Secretary of War, enclosing “Memorandum on `Political and Social Problems,’ from Members of the `Metallurgical Laboratory’ of the University of Chicago,” June 12, 1945, Secret

Source: RG 77, MED Records, H-B files, folder no. 76 (copy from microfilm)

Physicists Leo Szilard and James Franck, a Nobel Prize winner, were on the staff of the “Metallurgical Laboratory” at the University of Chicago, a cover for the Manhattan Project program to produce fuel for the bomb. The outspoken Szilard was not involved in operational work on the bomb and General Groves kept him under surveillance but Met Lab director Arthur Compton found Szilard useful to have around. Concerned with the long-run implications of the bomb, Franck chaired a committee, in which Szilard and Eugene Rabinowitch were major contributors, that produced a report rejecting a surprise attack on Japan and recommended instead a demonstration of the bomb on the “desert or a barren island.” Arguing that a nuclear arms race “will be on in earnest not later than the morning after our first demonstration of the existence of nuclear weapons,” the committee saw international control as the alternative. That possibility would be difficult if the United States made first military use of the weapon. Compton raised doubts about the recommendations but urged Stimson to study the report. Martin Sherwin has argued that the Franck committee shared an important assumption with Truman et al.--that an “atomic attack against Japan would `shock’ the Russians”--but drew entirely different conclusions about the import of such a shock. [26]

Document 23: Memorandum from Acting Secretary of State Joseph Grew to the President, “Analysis of Memorandum Presented by Mr. Hoover,” June 13, 1945

Source: Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 8, Japan (After December 7/41)

A former ambassador to Japan, Joseph Grew’s extensive knowledge of Japanese politics and culture informed his stance toward the concept of unconditional surrender. He believed it essential that the United States declare its intention to preserve the institution of the emperor. As he argued in this memorandum to President Truman, “failure on our part to clarify our intentions” on the status of the emperor “will insure prolongation of the war and cost a large number of human lives.” Documents like this have played a role in arguments developed by Alperovitz that Truman and his advisers had alternatives to using the bomb such as modifying unconditional surrender and that anti-Soviet considerations weighed most heavily in their thinking. By contrast, Herbert P. Bix has suggested that the Japanese leadership would “probably not” have surrendered if the Truman administration had spelled out the status of the emperor.[27]

Document 24: Memorandum from Chief of Staff Marshall to the Secretary of War, 15 June 1945, enclosing “Memorandum of Comments on `Ending the Japanese War,’” prepared by George A. Lincoln, June 14, 1945, Top Secret

Source: Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 8, Japan (After December 7/41)

Commenting on another memorandum by Herbert Hoover, George A. Lincoln discussed war aims, face-saving proposals for Japan, and the nature of the proposed declaration to the Japanese government, including the problem of defining “unconditional surrender.” Lincoln argued against modifying the concept of unconditional surrender: if it is “phrased so as to invite negotiation” he saw risks of prolonging the war or a “compromise peace.” J. Samuel Walker has observed that those risks help explain why senior officials were unwilling to modify the demand for unconditional surrender.[28]

Document 25: Memorandum by J. R. Oppenheimer, “Recommendations on the Immediate Use of Nuclear Weapons,” June 16, 1945, Top Secret

Source: RG 77, MED Records, H-B files, folder no. 76 (copy from microfilm)

In a report to Stimson, Oppenheimer and colleagues on the scientific advisory panel--Arthur Compton, Ernest O. Lawrence, and Enrico Fermi—tacitly disagreed with the report of the “Met Lab” scientists. The panel argued for early military use but not before informing key allies about the atomic project to open a dialogue on “how we can cooperate in making this development contribute to improved international relations.”

Document 26: “Minutes of Meeting Held at the White House on Monday, 18 June 1945 at 1530,” Top Secret

Source: Record Group 218, Records of the Joint Chiefs of Staff, Central Decimal Files, 1942-1945, box 198 334 JCS (2-2-45) Mtg 186th-194th

With the devastating battle for Okinawa winding up, Truman and the Joint Chiefs stepped back and considered what it would take to secure Japan’s surrender. The discussion depicted a Japan that, by 1 November, would be close to defeat, with great destruction and economic losses produced by aerial bombing and naval blockade, but not ready to capitulate. Marshall believed that the latter required Soviet entry and an invasion of Kyushu, even suggesting that Soviet entry might be the “decisive action levering them into capitulation.” Truman and the Chiefs reviewed plans to land troops on Kyushu on 1 November, which Marshall believed was essential because air power was not decisive. He believed that casualties would not be more than those produced by the battle for Luzon, some 31,000. This account hints at discussion of the atomic bomb (“certain other matters”), but no documents disclose that part of the meeting.

The record of this meeting has figured in the complex debate over the estimates of casualties stemming from a possible invasion of Japan. While post-war justifications for the bomb suggested that an invasion of Japan could have produced very high levels of casualties (dead, wounded, or missing), from hundreds of thousands to a million, historians have vigorously debated the extent to which the estimates were inflated. [29]

According to accounts based on post-war recollections and interviews, during the meeting McCloy raised the possibility of winding up the war by guaranteeing the preservation of the emperor albeit as a constitutional monarch. If that failed to persuade Tokyo, he proposed that the United States disclose the secret of the atomic bomb to secure Japan’s unconditional surrender. While McCloy later recalled that Truman expressed interest, he said that Secretary of State Byrnes squashed the proposal because of his opposition to any “deals” with Japan. Yet, according to Forrest Pogue’s account, when Truman asked McCloy if he had any comments, the latter opened up a discussion of nuclear weapons use by asking “Why not use the bomb?”[30]

Document 27: Memorandum from R. Gordon Arneson, Interim Committee Secretary, to Mr. Harrison, June 25, 1945, Top Secret

Source: RG 77, MED Records, H-B files, folder no. 100 (copy from microfilm)

For Harrison’s convenience, Arneson summarized key decisions made at the 21 June meeting of the Interim Committee, including a recommendation that President Truman use the forthcoming conference of allied leaders to inform Stalin about the atomic project. The Committee also reaffirmed earlier recommendations about the use of the bomb at the “earliest opportunity” against “dual targets.” In addition, Arneson included the Committee’s recommendation for revoking part two of the 1944 Quebec agreement which stipulated that the neither the United States nor Great Britain would use the bomb “against third parties without each other’s consent.” Thus, an impulse for unilateral control of nuclear use decisions predated the first use of the bomb.

Document 28: Memorandum from George L. Harrison to Secretary of War, June 26, 1945, Top Secret

Source: RG 77, MED, H-B files, folder no. 77 (copy from microfilm)

Reminding Stimson about the objections of some Manhattan project scientists to military use of the bomb, Harrison summarized the basic arguments of the Franck report. One recommendation shared by many of the scientists, whether they supported the report or not, was that the United States inform Stalin of the bomb before it was used. This proposal had been the subject of positive discussion by the Interim Committee on the grounds that Soviet confidence was necessary to make possible post-war cooperation on atomic energy.

Document 29: Memorandum from George L. Harrison to Secretary of War, June 28, 1945, Top Secret, enclosing Ralph Bard’s “Memorandum on the Use of S-1 Bomb,” June 27, 1945

Source: RG 77, MED, H-B files, folder no. 77 (copy from microfilm)

Under Secretary of the Navy Ralph Bard joined those scientists who sought to avoid military use of the bomb; he proposed a “preliminary warning” so that the United States would retain its position as a “great humanitarian nation.” Alperovitz cites evidence that Bard discussed his proposal with Truman who told him that he had already thoroughly examined the problem of advanced warning. This document has also figured in the argument framed by Barton Bernstein that Truman and his advisers took it for granted that the bomb was a legitimate weapon and that there was no reason to explore alternatives to military use. Bernstein, however, notes that Bard later denied that he had a meeting with Truman and that White House appointment logs support that claim.[31]

Document 30: Memorandum for Mr. McCloy, “Comments re: Proposed Program for Japan,” June 28, 1945, Draft, Top Secret

Source: RG 107, Office of Assistant Secretary of War Formerly Classified Correspondence of John J. McCloy, 1941-1945, box 38, ASW 387 Japan

Despite the interest of some senior officials such as Joseph Grew, Henry Stimson, and John J. McCloy in modifying the concept of unconditional surrender so that the Japanese could be sure that the emperor would be preserved, it remained a highly contentious subject. For example, one of McCloy’s aides, Colonel Fahey, argued against modification of unconditional surrender (see “Appendix ‘C`”).

Document 31: Assistant Secretary of War John J. McCloy to Colonel Stimson, June 29, 1945, Top Secret

Source: Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 8, Japan (After December 7/41)

McCloy was part of a drafting committee at work on the text of a proclamation to Japan to be signed by heads of state at the forthcoming Potsdam conference. As McCloy observed the most contentious issue was whether the proclamation should include language about the preservation of the emperor: “This may cause repercussions at home but without it those who seem to know the most about Japan feel there would be very little likelihood of acceptance.”

Document 32: Memorandum, “Timing of Proposed Demand for Japanese Surrender,” June 29, 1945, Top Secret

Source: Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 8, Japan (After December 7/41)

Probably the work of General George A. Lincoln at Army Operations, this document was prepared a few weeks before the Potsdam conference when senior officials were starting to finalize the text of the declaration that Truman, Churchill, and Chiang would issue there. The author recommended issuing the declaration “just before the bombardment program [against Japan] reaches its peak.” Next to that suggestion, Stimson or someone in his immediate office, wrote “S1”, implying that the atomic bombing of Japanese cities was highly relevant to the timing issue. Also relevant to Japanese thinking about surrender, the author speculated, was the Soviet attack on their forces after a declaration of war.

Document 33: Stimson memorandum to The President, “Proposed Program for Japan,” 2 July 1945, Top Secret

Source: Naval Aide to the President Files, box 4, Berlin Conference File, Volume XI - Miscellaneous papers: Japan, Harry S. Truman Presidential Library

Hiroshima, after the first atomic bomb explosion. This photo was taken from the Red Cross Hospital Building about one mile from the bomb burst. (Photo from U.S. National Archives, Still Pictures Branch, Subject Files, "Atomic Bomb")

On 2 July Stimson presented to President Truman a proposal that he had worked up with colleagues in the War Department, including McCloy, Marshall, and Grew. The proposal has been characterized as “the most comprehensive attempt by any American policymaker to leverage diplomacy” in order to shorten the Pacific War. Stimson had in mind a “carefully timed warning” delivered before the invasion of Japan. Some of the key elements of Stimson’s argument were his assumption that “Japan is susceptible to reason” and that Japanese might be even more inclined to surrender if “we do not exclude a constitutional monarchy under her present dynasty.” The possibility of a Soviet attack would be part of the “threat.” As part of the threat message, Stimson alluded to the “inevitability and completeness of the destruction” which Japan could suffer, but he did not make it clear whether unconditional surrender terms should be clarified before using the atomic bomb. Truman read Stimson’s proposal, which he said was “powerful,” but made no commitments to the details, e.g., the position of the emperor. [32]

Document 34: Minutes, Secretary’s Staff Committee, Saturday Morning, July 7, 1945, 133d Meeting, Top Secret

Source: Record Group 353, Records of Interdepartmental and Intradepartmental Committees, Secretary’s Staff Meetings Minutes, 1944-1947 (copy from microfilm)

The possibility of modifying the concept of unconditional surrender so that it guaranteed the continuation of the emperor remained hotly contested within the U.S. government. Here senior State Department officials, Under Secretary Joseph Grew on one side, and Assistant Secretary Dean Acheson and Archibald MacLeish on the other, engaged in hot debate.

Document 35: Combined Chiefs of Staff, “Estimate of the Enemy Situation (as of 6 July 1945, C.C.S 643/3, July 8, 1945, Secret (Appendices Not Included)

Source: RG 218, Central Decimal Files, 1943-1945, CCS 381 (6-4-45), Sec. 2 Pt. 5

This review of Japanese capabilities and intentions portrays an economy and society under “tremendous strain”; nevertheless, “the ground component of the Japanese armed forces remains Japan’s greatest military asset.” Alperovitz sees statements in this estimate about the impact of Soviet entry into the war and the possibility of a conditional surrender involving survival of the emperor as an institution as more evidence that the policymakers saw alternatives to nuclear weapons use. By contrast, Richard Frank takes note of the estimate’s depiction of the Japanese army’s terms for peace: “for surrender to be acceptable to the Japanese army it would be necessary for the military leaders to believe that it would not entail discrediting the warrior tradition and that it would permit the ultimate resurgence of a military in Japan.” That, Frank argues, would have been “unacceptable to any Allied policy maker.”[33]

Document 36: Cable to Secretary of State from Acting Secretary Joseph Grew, July 16, 1945, Top Secret

Source: Record Group 59, Decimal Files 1945-1949, 740.0011 PW (PE)/7-1645

On the eve of the Potsdam Conference, a State Department draft of the proclamation to Japan contained language which modified unconditional surrender by promising to retain the emperor. When former Secretary of State Cordell Hull learned about it he outlined his objections to Byrnes, arguing that it might be better to wait “the climax of allied bombing and Russia’s entry into the war.” Byrnes was already inclined to reject that part of the draft, but Hull’s argument that may have reinforced his decision.

Document 37: Letter from Stimson to Byrnes, enclosing memorandum to the President, “The Conduct of the War with Japan,” 16 July 1945, Top Secret

Source: Henry L. Stimson Papers (MS 465), Sterling Library, Yale University (reel 113) (microfilm at Library of Congress)

Still interested in trying to find ways to “warn Japan into surrender,” this represents an attempt by Stimson before the Potsdam conference, to persuade Truman and Byrnes to agree to issue warnings to Japan prior to the use of the bomb. The warning would draw on the draft State-War proclamation to Japan; presumably, the one criticized by Hull (above) which included language about the emperor. Presumably the clarified warning would be issued prior to the use of the bomb; if the Japanese persisted in fighting then “the full force of our new weapons should be brought to bear” and a “heavier” warning would be issued backed by the “actual entrance of the Russians in the war.” Possibly, as Malloy has argued, Stimson was motivated by concerns about using the bomb against civilians and cities, but his latest proposal would meet resistance at Potsdam from Byrnes and other.[34]

Document 38: R. E. Lapp, Leo Szilard et al., “A Petition to the President of the United States,” July 17, 1945

Source: RG 77, MED Records, H-B files, folder no. 76 (copy from microfilm)

On the eve of the Potsdam conference, Leo Szilard circulated a petition as part of a final effort to discourage military use of the bomb. Signed by about 68 Manhattan Project scientists, mainly physicists and biologists (copies with the remaining signatures are in the archival file), the petition did not explicitly reject military use, but raised questions about an arms race that military use could instigate and requested Truman to publicize detailed terms for Japanese surrender. Truman, already on his way to Europe, never saw the petition.[35]

IV. The Japanese Search for Soviet Mediation

Documents 39A-B: Magic

39A: William F. Friedman, Consultant (Armed Forces Security Agency), “A Short History of U.S. COMINT Activities,” 19 February 1952, Top Secret

39B:“Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1204 – July 12, 1945, Top Secret Ultra

Sources: A: National Security Agency Mandatory declassification review release; B: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18

Ground Zero at Hiroshima Today: This was the site of Shima Hospital; the atomic explosion occurred 1,870 feet above it (Photo courtesy of Lynn Eden, www.wholeworldonfire.com)

Beginning in September 1940, U.S. military intelligence began to decrypt routinely, under the “Purple” code-name, the intercepted cable traffic of the Japanese Foreign Ministry. Collectively the decoded messages were known as “Magic.” How this came about is explained in an internal history of pre-war and World War II Army and Navy code-breaking activities prepared by William F. Friedman, a central figure in the development of U.S. government cryptology during the 20th century. The National Security Agency kept the ‘Magic” diplomatic and military summaries classified for many years and did not release the entire series for 1942 through August 1945 until the early 1990s.[36]

The 12 July 1945 “Magic” summary includes a report on a cable from Japanese Foreign Minister Shigenori Togo to Ambassador Naotake Sato in Moscow concerning the Emperor’s decision to seek Soviet help in ending the war. Not knowing that the Soviets had already made a commitment to their Allies to declare war on Japan, Tokyo fruitlessly pursued this option for several weeks. The “Magic” intercepts from mid-July have figured in Gar Alperovitz’s argument that Truman and his advisers recognized that the Emperor was ready to capitulate if the Allies showed more flexibility on the demand for unconditional surrender. This point is central to Alperovitz’s thesis that top U.S. officials recognized a “two-step logic”: relaxing unconditional surrender and a Soviet declaration of war would have been enough to induce Japan’s surrender without the use of the bomb.[37]

Document 40: John Weckerling, Deputy Assistant Chief of Staff, G-2, July 12, 1945, to Deputy Chief of Staff, “Japanese Peace Offer,” 13 July 1945, Top Secret Ultra

Source: RG 165, Army Operations OPD Executive File #17, Item 13 (copy courtesy of J. Samuel Walker)

The day after the Togo message was reported, Army intelligence chief Weckerling proposed several possible explanations of the Japanese diplomatic initiative. Robert J. Maddox has cited this document to support his argument that top U.S. officials recognized that Japan was not close to surrender because Japan was trying to “stave off defeat.” In a close analysis of this document, Tsuyoshi Hasegawa, who is also skeptical of claims that the Japanese had decided to surrender, argues that each of the three possibilities proposed by Weckerling “contained an element of truth, but none was entirely correct”. For example, the “governing clique” that supported the peace moves was not trying to “stave off defeat” but was seeking Soviet help to end the war.[38]

Document 41: “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1205 – July 13, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18

The day after he told Sato about the current thinking on Soviet mediation, Togo requested the Ambassador to see Soviet Foreign Minister Vyacheslav Molotov and tell him of the Emperor’s “private intention to send Prince Konoye as a Special Envoy” to Moscow. Before he received Togo’s message, Sato had already met with Molotov on another matter.

Document 42: “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1210 – July 17, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18.

Another intercept of a cable from Togo to Sato shows that the Foreign Minister rejected unconditional surrender and that the Emperor was not “asking the Russian’s mediation in anything like unconditional surrender.” Incidentally, this “`Magic’ Diplomatic Summary” indicates the broad scope and capabilities of the program; for example, it includes translations of intercepted French messages (see pages 8-9).

Document 43: Admiral Tagaki Diary Entry for July 20, 1945

Source: Takashi Itoh, ed., Sokichi Takagi: Nikki to Joho [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 916-917 [Translation by Hikaru Tajima]

In 1944 Navy minister Mitsumasa Yonai ordered rear admiral Sokichi Takagi to go on sick leave so that he could undertake a secret mission to find a way to end the war. Tagaki was soon at the center of a cabal of Japanese defense officials, civil servants, and academics, which concluded that, in the end, the emperor would have to “impose his decision on the military and the government.” Takagi kept a detailed account of his activities, part of which was in diary form, the other part of which he kept on index cards. The material reproduced here gives a sense of the state of play of Foreign Minister Togo’s attempt to secure Soviet mediation. Hasegawa cited it and other documents to make a larger point about the inability of the Japanese government to agree on “concrete” proposals to negotiate an end to the war.[39]

The last item discusses Japanese contacts with representatives of the Office of Strategic Services (OSS) in Switzerland. The reference to “our contact” may refer to Bank of International Settlements economist Pers Jacobbson who was in touch with Japanese representatives to the Bank as well as Gero von Gävernitz, then on the staff, but with non-official cover, of OSS station chief Allen Dulles. The contacts never went far and Dulles never received encouragement to pursue them.[40]

V. The Trinity Test

Document 44: Letter from Commissar of State Security First Rank, V. Merkulov, to People’s Commissar for Internal Affairs L. P. Beria, 10 July 1945, Number 4305/m, Top Secret (translation by Anna Melyaskova)

Source: L.D. Riabev, ed., Atomnyi Proekt SSSR (Moscow: izd MFTI, 2002), Volume 1, Part 2, 335-336

This 10 July 1945 letter from NKGB director V. N. Merkulov to Beria is an example of Soviet efforts to collect inside information on the Manhattan Project, although not all the detail was accurate. Merkulov reported that the United States had scheduled the test of a nuclear device for that same day, although the actual test took place 6 days later. According to Merkulov, two fissile materials were being produced: element-49 (plutonium), and U-235; the test device was fueled by plutonium. The Soviet source reported that the weight of the device was 3 tons (which was in the ball park) and forecast an explosive yield of 5 kilotons. That figure was based on underestimates by Manhattan Project scientists: the actual yield of the test device was 20 kilotons.

As indicated by the L.D. Riabev’s notes, it is possible that Beria’s copy of this letter ended up in Stalin’s papers. That the original copy is missing from Beria’s papers suggests that he may have passed it on to Stalin before the latter left for the Potsdam conference.[41]

Document 45: Telegram War [Department] 33556, from Harrison to Secretary of War, July 17, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File 5e (copy from microfilm)

An elated message from Harrison to Stimson reported the success of the Trinity Test of a plutonium implosion weapon. The light from the explosion could been seen “from here [Washington, D.C.] to “high hold” [Stimson’s estate on Long Island—250 miles away]” and it was so loud that Harrison could have heard the “screams” from Washington, D.C. to “my farm” [in Upperville, VA, 50 miles away][42]

Document 46: Memorandum from General L. R. Groves to Secretary of War, “The Test,” July 18, 1945, Top Secret, Excised Copy

Source: RG 77, MED Records, Top Secret Documents, File no. 4 (copy from microfilm)

General Groves prepared for Stimson, then at Potsdam, a detailed account of the Trinity test.[43]

VI. The Potsdam Conference

Document 47: Truman’s Potsdam Diary

Barton J. Bernstein, “Truman at Potsdam: His Secret Diary,” Foreign Service Journal, July/August 1980, excerpts, used with author’s permission.[44]

Some years after Truman’s death, a hand-written diary that he kept during the Potsdam conference surfaced in his personal papers. For convenience Barton Bernstein’s rendition is provided here but linked here are the scanned versions of Truman’s handwriting on the Truman Library’s web site (for 16 Julyand 17-30 July).

The diary entries cover July 16, 17, 18, 20, 25, 26, and 30 and include Truman’s thinking about a number of issues and developments, including his reactions to Churchill and Stalin, the atomic bomb and how it should be targeted, the possible impact of the bomb and a Soviet declaration of war on Japan, and his decision to tell Stalin about the bomb. Receptive to pressure from Stimson, Truman recorded his decision to take Japan’s “old capital” (Kyoto) off the atomic bomb target list. Barton Bernstein and Richard Frank, among others, have argued that Truman’s assertion that the atomic targets were “military objectives” suggested that either he did not understand the power of the new weapons or had simply deceived himself about the nature of the targets. Another statement—“Fini Japs when that [Soviet entry] comes about”—has also been the subject of controversy over whether it meant that Truman thought it possible that the war could end could end without an invasion of Japan.[45]

Document 48: Stimson Diary entries for July 16 through 25, 1945

Source: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

Stimson did not always have Truman’s ear, but historians have frequently cited his diary when he was at the Potsdam conference. There Stimson kept track of S-1 developments, including news of the successful first test (see entry for July 16) and the ongoing deployments for nuclear use against Japan. When Truman received a detailed account of the test, Stimson reported that the “President was tremendously pepped up by it” and that “it gave him an entirely new feeling of confidence” (see entry for July 21). Whether this meant that Truman was getting ready for a confrontation with Stalin over Eastern Europe and other matters has also been the subject of debate.

An important question that Stimson discussed with Marshall, at Truman’s request, was whether Soviet entry into the war remained necessary to secure Tokyo’s surrender. Marshall was not sure whether that was so although Stimson privately believed that the atomic bomb would provide enough to force surrender (see entry for July 23). This entry has been cited by all sides of the controversy over whether Truman was trying to keep the Soviets out of the war.[46] During the meeting on August 24, discussed above, Stimson gave his reasons for taking Kyoto off the atomic target list: destroying that city would have caused such “bitterness” that it could have become impossible “to reconcile the Japanese to us in that area rather than to the Russians.” Stimson vainly tried to preserve language in the Potsdam Declaration designed to assure the Japanese about “the continuance of their dynasty” but received Truman’s assurance that such a consideration could be conveyed later through diplomatic channels (see entry for July 24). Hasegawa argues that Truman realized that the Japanese would refuse a demand for unconditional surrender without a proviso on a constitutional monarchy and that “he needed Japan’s refusal to justify the use of the atomic bomb.”[47]

Document 49: Walter Brown Diaries, July 10-August 3, 1945

Source: Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 10, folder 12, Byrnes, James F.: Potsdam, Minutes, July-August 1945

The mushroom cloud over Nagasaki shortly after the bombing on August 9. (Photo from U.S. National Archives, RG 77-AEC)

Walter Brown, who served as special assistant to Secretary of State Byrnes, kept a diary which provided considerable detail on the Potsdam conference and the growing concerns about Soviet policy among top U.S. officials. This document is a typed-up version of the hand-written original (which Brown’s family has provided to Clemson University). That there may be a difference between the two sources becomes evident from some of the entries; for example, in the entry for July 18, 1945 Brown wrote: "Although I knew about the atomic bomb when I wrote these notes, I dared not place it in writing in my book.” The degree to which the typed-up version reflects the original is worth investigating. In any event, historians have used information from the diary to support various interpretations. For example, Bernstein cites the entries for 20 and 24 July to argue that “American leaders did not view Soviet entry as a substitute for the bomb” but that the latter “would be so powerful, and the Soviet presence in Manchuria so militarily significant, that there was no need for actual Soviet intervention in the war.” Frank points to the entry for 3 August, with its discussion of Japan’s interest in Soviet diplomatic assistance, as crucial evidence that Admiral Leahy had been sharing “MAGIC” information with President Truman. He also argues out that Truman and his colleagues had no idea what was behind Japanese peace moves, only that Suzuki had declared that he would “ignore” the Potsdam Declaration. Alperovitz, however, treats the 3 August entry as evidence that “strongly suggests” that Truman saw alternatives to using the bomb.[48]

Document 50: “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1214 – July 22, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18.

This “Magic” summary includes messages from both Togo and Sato. In a long and impassioned message, the latter argued why Japan must accept defeat: “it is meaningless to prove one’s devotion [to the Emperor] by wrecking the State.” Togo rejected Sato’s advice that Japan could accept unconditional surrender with one qualification: the “preservation of the Imperial House.” Probably unable or unwilling to take a soft position in an official cable, Togo declared that “the whole country … will pit itself against the enemy in accordance with the Imperial Will as long as the enemy demands unconditional surrender.”

Document 51: Forrestal Diary Entry, July 24, 1945, “Japanese Peace Feelers”

Source: Naval Historical Center, Operational Archives, James Forrestal Diaries

Secretary of the Navy James Forrestal was a regular recipient of “Magic” intercept reports; this substantial entry reviews the dramatic Sato-Togo exchanges covered in the 22 July “Magic” summary (although Forrestal misdated Sato’s cable as “first of July” instead of the 21st). In contrast to Alperovitz’s argument that Forrestal tried to modify the terms of unconditional surrender to give the Japanese an out, Frank sees Forrestal’s account of the Sato-Togo exchange as additional evidence that senior U.S. officials understood that Tokyo was not on the “cusp of surrender.” [49]

Document 52: Davies Diary entry for July 29, 1945

Source: Joseph E. Davies Papers, Library of Congress, Manuscripts Division, box 19, 29 July 1945

Having been asked by Truman to join the delegation to the Potsdam conference, former-Ambassador Davies sat at the table with the Big Three throughout the discussions. This diary entry has figured in the argument that Byrnes believed that the atomic bomb gave the United States a significant advantage in negotiations with the Soviet Union. Plainly Davies thought otherwise.[50]

VII. Debates among the Japanese – Late July/Early August 1945

Document 53: “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1221- July 29, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18.

In the Potsdam Declaration http://www.isop.ucla.edu/eas/documents/potsdam.htm the governments of China, Great Britain, and the United States) demanded the “unconditional surrender of all Japanese armed forces. “The alternative is prompt and utter destruction.” The next day, in response to questions from journalists about the government’s reaction to the ultimatum, Prime Minister Suzuki apparently said that “We can only ignore [mokusatsu] it. We will do our utmost to complete the war to the bitter end.” That, Bix argues, represents a “missed opportunity” to end the war and spare the Japanese from continued U.S. aerial attacks.[51] Togo’s private position was more nuanced than Suzuki’s; he told Sato that “we are adopting a policy of careful study.” That Stalin had not signed the declaration (Truman and Churchill did not ask him to) led to questions about the Soviet attitude. Togo asked Sato to try to meet with Soviet Foreign Minister Molotov as soon as possible to “sound out the Russian attitude” on the declaration as well as Japan’s end-the-war initiative. Sato cabled Togo earlier that he saw no point in approaching the Soviets on ending the war until Tokyo had “concrete proposals.” “Any aid from the Soviets has now become extremely doubtful.”

Document 54: “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1222 – July 30, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18.

This report included an intercept of a message from Sato reporting that it was impossible to see Molotov and that unless the Togo had a “concrete and definite plan for terminating the war” he saw no point in attempting to meet with him.

Document 55: “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1225 – August 2, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18.

An intercepted message from Togo to Sato showed that Tokyo remained interested in securing Moscow’s good office but that it “is difficult to decide on concrete peace conditions here at home all at once.” “[W]e are exerting ourselves to collect the views of all quarters on the matter of concrete terms.” Barton Bernstein, Richard Frank, and Tsuyoshi Hasegawa, among others, have argued that the “Magic” intercepts from the end of July and early August show that the Japanese were far from ready to surrender. According to Herbert Bix, for months Hirohito had believed that the “outlook for a negotiated peace could be improved if Japan fought and won one last decisive battle,” thus, he delayed surrender, continuing to “procrastinate until the bomb was dropped and the Soviets attacked.”[52]

Document 56: “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1226 - August 3, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18.

This summary included intercepts of Japanese diplomatic reporting on the Soviet buildup in the Far East as well as a naval intelligence report on Anglo-American discussions of U.S. plans for the invasion of Japan. Part II of the summary includes the rest of Togo’s 2 August cable which instructed Sato to do what he could to arrange an interview with Molotov.

Document 57: Walter Brown Meeting Notes, August 3, 1945

Source: Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 10, folder 12, Byrnes, James F.: Potsdam, Minutes, July-August 1945

Historians have used this item in the papers of Byrne’s aide, Walter Brown, to make a variety of points. Richard Frank sees this brief discussion of Japan’s interest in Soviet diplomatic assistance as crucial evidence that Admiral Leahy had been sharing “MAGIC” information with President Truman. He also points out that Truman and his colleagues had no idea what was behind Japanese peace moves, only that Suzuki had declared that he would “ignore” the Potsdam Declaration. Alperovitz, however, treats it as additional evidence that “strongly suggests” that Truman saw alternatives to using the bomb.[53]

Document 58: “Magic” – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 502, 4 August 1945

Source: RG 457, Summaries of Intercepted Japanese Messages (“Magic” Far East Summary, March 20, 1942 – October 2, 1945), box 7, SRS 491-547

This “Far East Summary” included reports on the Japanese Army’s plans to disperse fuel stocks to reduce vulnerability to bombing attacks, the text of a directive by the commander of naval forces on “Operation Homeland,” the preparations and planning to repel a U.S. invasion of Honshu, and the specific identification of army divisions located in, or moving into, Kyushu. Both Richard Frank and Barton Bernstein have used intelligence reporting and analysis of the major buildup of Japanese forces on southern Kyushu to argue that U.S. military planners were so concerned about this development that by early August 1945 they were reconsidering their invasion plans.[54]

Document 59: “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1228 – August 5, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18.

This summary included several intercepted messages from Sato, who conveyed his despair and exasperation over what he saw as Tokyo’s inability to develop terms for ending the war: “[I]f the Government and the Military dilly-dally in bringing this resolution to fruition, then all Japan will be reduced to ashes.” Sato remained skeptical that the Soviets would have any interest in discussions with Tokyo: “it is absolutely unthinkable that Russia would ignore the Three Power Proclamation and then engage in conversations with our special envoy.”

VIII. The Execution Order

Documents 60a-d: Framing the Directive for Nuclear Strikes:

60A. Cable VICTORY 213 from Marshall to Handy, July 22, 1945, Top Secret

60B. Memorandum from Colonel John Stone to General Arnold, “Groves Project,” 24 July 1945, Top Secret

60C. Cable WAR 37683 from General Handy to General Marshal, enclosing directive to General Spatz, July 24, 1945, Top Secret

60D. Cable VICTORY 261 from Marshall to General Handy, July 25, 1945, 25 July 1945, Top Secret

60E. General Thomas T. Handy to General Carl Spaatz, July 26, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, Files no. 5b and 5e ((copies from microfilm)

Top Army Air Force commanders may not have wanted to take responsibility for the first use of nuclear weapons on urban targets and sought formal authorization from Chief of Staff Marshall who was then in Potsdam.[55] On 22 July Marshall asked Deputy Chief of Staff Thomas Handy to prepare a draft; General Groves wrote one which went to Potsdam for Marshall’s approval. Colonel John Stone, an assistant to commanding General of the Army Air Forces Henry H. “Hap” Arnold, had just returned from Potsdam and updated his boss on the plans as they had developed. On 25 July Marshall informed Handy that Secretary of War Stimson had approved the text; that same day, Handy signed off on a directive which ordered the use of atomic weapons on Japan, with the first weapon assigned to one of four possible targets—Hiroshima, Kokura, Niigata, or Nagasaki. “Additional bombs will be delivery on the [targets] as soon as made ready by the project staff.”

Document 61: Memorandum from Major General L. R. Groves to Chief of Staff, July 30, 1945, Top Secret, Sanitized Copy

Source: RG 77, MED Records, Top Secret Documents, File no. 5

With more information on the Alamogordo test available, Groves provided Marshall with detail on the destructive power of atomic weapons. Barton J. Bernstein has observed that Groves’ recommendation that troops could move into the “immediate explosion area” within a half hour demonstrates the prevalent lack of top-level knowledge of the dangers of nuclear weapons effects.[56] Groves also provided the schedule for the delivery of the weapons: the components of the gun-type bomb to be used on Hiroshima had arrived on Tinian, while the parts of the second weapon to be dropped were leaving San Francisco. By the end of November over ten weapons would be available, presumably in the event the war had continued.

Documents 62A-C: Weather delays

62A. CG 313th Bomb Wing, Tinian cable APCOM 5112 to War Department, August 3, 1945, Top Secret

62B. CG 313th Bomb Wing, Tinian cable APCOM 5130 to War Department, August 4, 1945, Top Secret

62C. CG 313th Bomb Wing, Tinian cable APCOM 5155 to War Department, August 4, 1945, Top Secret

Source: RG 77, Tinian Files, April-December 1945, box 21 (copies courtesy of Barton Bernstein)

The Hiroshima “operation” was originally slated to begin in early August depending on local conditions. As these cables indicate, reports of unfavorable weather delayed the plan. The second cable on 4 August shows that the schedule advanced to late in the evening of 5 August. The handwritten transcriptions are on the original archival copies.

IX. The First Nuclear Strikes and their Impact

Document 63: Memorandum from General L. R. Groves to the Chief of Staff, August 6, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5b (copy from microfilm)

Two days after the bombing of Hiroshima, Groves provided Chief of Staff Marshall with a report which included messages from Captain William S. Parsons and others about the impact of the detonation which, through prompt radiation effects, fire storms, and blast effects, immediately killed at least 70,000, with many dying later from radiation sickness and other causes.[57]

An overview of the destruction of Hiroshima [undated, circa August-September 1945]. (Photo from U.S. National Archives, RG 306-NT)

How influential the atomic bombings of Hiroshima and later Nagasaki compared to the impact of the Soviet declaration of war were to the Japanese decision to surrender has been the subject of controversy among historians. Sadao Asada emphasizes the shock of the atomic bombs, while Herbert Bix has suggested that Hiroshima and the Soviet declaration of war made Hirohito and his court believe that failure to end the war could lead to the destruction of the imperial house. Frank and Hasegawa divide over the impact of the Soviet declaration of war, with Frank declaring that the Soviet intervention was “significant but not decisive” and Hasegawa arguing that the two atomic bombs “were not sufficient to change the direction of Japanese diplomacy. The Soviet invasion was.”[58]

Document 64: Walter Brown Diary Entry, 6 August 1945

Source: Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 68, folder 13, “Transcript/Draft B

Returning from the Potsdam Conference, sailing on the U.S.S. Augusta, Truman learned about the atomic bombing of Hiroshima and announced it twice, first to those in the wardroom (socializing/dining area for commissioned officers), and then to the sailors’ mess. Still unaware of radiation effects, Truman emphasized the explosive yield. Later, he met with Secretary of State Byrnes and they discussed the Manhattan Project’s secrecy and the huge expenditures. Truman, who had been chair of the Senate Special Committee to Investigate the National Defense Program, said that Stimson had “appeal[ed] to him to refrain from investigating the secret project, but the Secretary of War stonewalled and refused to tell Truman anything.

Document 65: Directive from the Supreme Command Headquarters to the Commander-in-Chief of the Soviet Forces in the Far East on the Start of Combat Operations, No. 11122, Signed by [Communist Party General Secretary Joseph] Stalin and [Chief of General Staff A.I.] Antonov, 7 August 1945 (translation by Anna Melyaskova)

Source: V. A. Zolotarev, ed., Sovetsko-Iaponskaia Voina 1945 Goda: Istoriia Voenno-Politicheskogo Protivoborstva Dvukh Derzhav v 30–40e Gody (Moscow: Terra, 1997 and 2000), Vol. 7 (1), 340-341.

To keep his pledge at Yalta to enter the war against Japan and to secure the territorial concessions promised at the conference (e.g., Soviet annexation of the Kuriles and southern Sakhalin and a Soviet naval base at Port Arthur, etc.) Stalin considered various dates to schedule an attack. By early August he decided that 9-10 August 1945 would be the best dates for striking Japanese forces in Manchuria. In light of Japan’s efforts to seek Soviet mediation, Stalin wanted to enter the war quickly lest Tokyo reach a compromise peace with the Americans and the British at Moscow’s expense. But on 7 August, Stalin changed the instructions: the attack was to begin the next day. According to David Holloway, “it seems likely that the atomic bombing of Hiroshima the day before that impelled [Stalin] to speed up Soviet entry into the war” and “secure the gains promised at Yalta.”[59]

Document 66: Memorandum of Conversation, “Atomic Bomb,” August 7, 1945

Source: Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945.

The Soviets already knew about the U.S. atomic project from espionage sources in the United States and Britain so Molotov’s comment to Ambassador Harriman about the secrecy surrounding the U.S. atomic project can be taken with a grain of salt, although the Soviets were probably unaware of specific plans for nuclear use.

Documents 67A-B: Early High-level Reactions to the Hiroshima Bombing

67A: Cabinet Meeting and Togo's Meeting with the Emperor, August 7-8, 1945
Source: Gaimusho (Ministry of Foreign Affairs) ed. Shusen Shiroku (The Historical Records of the End of the War), annotated by Jun Eto, volume 4, 57-60 [Excerpts] [Translation by Toshihiro Higuchi]

67B: Admiral Tagaki Diary Entry for Wednesday, August 8 , 1945
Source: Takashi Itoh, ed., Sokichi Takagi: Nikki to Joho [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 923-924 [Translation by Hikaru Tajima]

Hiroshima - view of Hiroshima Castle and surroundings;
Upper image - July 24, 1945, photo by 28th Photo Reconnaissance Squadron
Lower image - August 11, 1945, photo by 6th Photo Reconnaissance Group
Source: U.S. National Archives, College Park, MD, Record Group 373, Defense Intelligence Agency, Aerial Film, U.S., Army Air Force. Courtesy of Tim Brown.

Excerpts from the Foreign Ministry's compilation about the end of the war show how news of the bombing reached Tokyo as well as how Foreign Minister's Togo initially reacted to reports about Hiroshima. When he learned of the atomic bombing from the Domei News Agency, Togo believed that it was time to give up and advised the cabinet that the atomic attack provided the occasion for Japan to surrender on the basis of the Potsdam Declaration. Togo could not persuade the cabinet, however, and the Army wanted to delay any decisions until it had learned what had happened to Hiroshima. When the Foreign Minister met with the Emperor, Hirohito agreed with him; he declared that the top priority was an early end to the war, although it would be acceptable to seek better surrender terms--probably U.S. acceptance of a figure-head emperor--if it did not interfere with that goal. In light of those instructions, Togo and Prime Minister Suzuki agreed that the Supreme War Council should meet the next day. [59a]

An entry from Admiral Tagaki's diary for August 8 conveys more information on the mood in elite Japanese circles after Hiroshima, but before the Soviet declaration of war and the bombing of Nagasaki. Seeing the bombing of Hiroshima as a sign of a worsening situation at home, Tagaki worried about further deterioration. Nevertheless, his diary suggests that military hard-liners were very much in charge and that Prime Minister Suzuki was talking tough against surrender, by evoking last ditch moments in Japanese history and warning of the danger that subordinate commanders might not obey surrender orders. The last remark aggravated Navy Minister Yonai who saw it as irresponsible. That the Soviets had made no responses to Sato's request for a meeting was understood as a bad sign; Yonai realized that the government had to prepare for the possibility that Moscow might not help. One of the visitors mentioned at the beginning of the entry was Iwao Yamazaki who became Minister of the Interior in the next cabinet.

Document 68: Navy Secretary James Forrestal to President Truman, August 8, 1945

Source: Naval Historical Center, Operational Archives, James Forrestal Diaries

General Douglas MacArthur had been slated as commander for military operations against Japan’s mainland, this letter to Truman from Forrestal shows that the latter believed that the matter was not settled. Richard Frank sees this as evidence of the uncertainty felt by senior officials about the situation in early August; Forrestal would not have been so “audacious” to take an action that could ignite a “political firestorm” if he “seriously thought the end of the war was near.”

Document 69: Memorandum of Conversation, “Far Eastern War and General Situation,” August 8, 1945, Top Secret

Source: Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945

Shortly after the Soviets declared war on Japan, in line with commitments made at the Yalta and Potsdam conferences, Ambassador Harriman met with Stalin, with George Kennan keeping the U.S. record of the meeting. After Stalin reviewed in considerable detail, Soviet military gains in the Far East, they discussed the possible impact of the atomic bombing on Japan’s position (Nagasaki had not yet been attacked) and the dangers and difficulty of an atomic weapons program. According to Hasegawa, this was an important, even “startling,” conversation: it showed that Stalin “took the atomic bomb seriously”; moreover, he disclosed that the Soviets were working on their own atomic program.[60]

Document 70: Entries for 8-9 August, Robert P. Meiklejohn Diary

Source: W.A. Harriman Papers, Library of Congress, box 211, Robert Pickens Meiklejohn World War II Diary At London and Moscow March 10, 1941-February 14, 1946, Volume II (Privately printed, 1980 [Printed from hand-written originals]) (Reproduced with permission)

Robert P. Meiklejohn, who worked as Ambassador W. A. Harriman’s administrative assistant at the U.S. Embassies in Moscow and London during and after World War II, kept a detailed diary of his experiences and observations. The entries for 8 and 9 August, prepared in light of the bombing of Hiroshima, include discussion of the British contribution to the Manhattan Project, Harriman (“his nibs’”) report on his meeting with Molotov about the Soviet declaration of war, and speculation about the impact of the bombing of Hiroshima on the Soviet decision. According to Meiklejohn, “None of us doubt that the atomic bomb speeded up the Soviets’ declaration of war.”

Document 71: Memorandum of Conference with the President, August 8, 1945 at 10:45 AM

Source: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

At their first meeting after the dropping of the bomb on Hiroshima, Stimson briefed Truman on the scale of the destruction, with Truman recognizing the “terrible responsibility” that was on his shoulder. Consistent with his earlier attempts, Stimson encouraged Truman to find ways to expedite Japan’s surrender by using “kindness and tact” and not treating them in the same way as the Germans. They also discussed postwar legislation on the atom and the pending Henry D. Smyth report on the scientific work underlying the Manhattan project and postwar domestic controls of the atom.

Documents 72A-C: The Attack on Nagasaki:

72A. Cable APCOM 5445 from General Farrell to O’Leary [Groves assistant], August 9, 1945, Top Secret

72B. COMGENAAF 8 cable CMDW 576 to COMGENUSASTAF, for General Farrell, August 9, 1945, Top secret

72C. COMGENAAF 20 Guam cable AIMCCR 5532 to COMGENUSASTAF Guam, August 10, 1945, Top Secret

Source: RG 77, Tinian Files, April-December 1945, box 20, Envelope G Tinian Files, Top Secret

The prime target for the second atomic attack was Kokura, which had a large army arsenal and ordnance works, but various problems ruled that city out; instead, the crew of the B-29 that carried “Fat Man” flew to an alternate target at Nagasaki. These cables are the earliest reports of the mission; the bombing of Nagasaki killed immediately at least 39,000 people, with more dying later. According to Frank, the “actual total of deaths due to the atomic bombs will never be known,” but the “huge number” ranges somewhere between 100,000 and 200,000 people. Barton J. Bernstein and Martin Sherwin have argued that if top Washington policymakers had kept tight control of the delivery of the bomb instead of delegating it to Groves the attack on Nagasaki could have been avoided. The combination of the first bomb and the Soviet declaration of war would have been enough to induce Tokyo’s surrender. By contrast, Maddox argues that Nagasaki was necessary so that Japanese “hardliners” could not “minimize the first explosion” or otherwise explain it away.[61]

Documents 73A-B: Ramsey Letter from Tinian Island

73A: Letter from Norman Ramsey to J. Robert Oppenheimer, undated [mid-August 1945], Secret, excerpts
Source: Library of Congress, J. Robert Oppenheimer Papers, box 60, Ramsey, Norman

73B: Transcript of the letter prepared by editor.

Ramsey, a physicist, served as deputy director of the bomb delivery group, Project Alberta. This personal account, written on Tinian, reports his fears about the danger of a nuclear accident, the confusion surrounding the Nagasaki attack, and early Air Force thinking about a nuclear strike force

X. Toward Surrender

Document 74: “Magic” – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 507, August 9, 1945

Source: RG 457, Summaries of Intercepted Japanese Messages (“Magic” Far East Summary, March 20, 1942 – October 2, 1945), box 7, SRS 491-547

Within days after the bombing of Hiroshima, U.S. military intelligence intercepted Japanese reports on the destruction of the city. According to an “Eyewitness Account (and Estimates Heard) … In Regard to the Bombing of Hiroshima”: “Casualties have been estimated at 100,000 persons.”

Document 75: “Hoshina Memorandum” on the Emperor’s “Sacred Decision [go-seidan],” 9-10 August, 1945

Source: Zenshiro Hoshina, Daitoa Senso Hishi: Hoshina Zenshiro Kaiso-roku [Secret History of the Greater East Asia War: Memoir of Zenshiro Hoshina] (Tokyo, Japan: Hara-Shobo, 1975), excerpts from Section 5, “The Emperor made go-seidan [= the sacred decision] – the decision to terminate the war,” 139-149 [translation by Hikaru Tajima]

Despite the bombing of Hiroshima, the Soviet declaration of war, and growing worry about domestic instability, the Japanese cabinet (whose decisions required unanimity) could not form a consensus to accept the Potsdam Declaration. Members of the Supreme War Council—“the Big Six”[62]—wanted the reply to Potsdam to include at least four conditions (e.g., no occupation, voluntary disarmament); they were willing to fight to the finish. The peace party, however, deftly maneuvered to break the stalemate by persuading a reluctant emperor to intervene. According to Hasegawa, Hirohito had become convinced that the preservation of the monarchy was at stake. Late in the evening of 9 August, the emperor and his advisers met in the bomb shelter of the Imperial Palace.

Zenshiro Hoshina, a senior naval official, attended the conference and prepared a detailed account. With Prime Minister Suzuki presiding, each of the ministers had a chance to state their views directly to Hirohito. While Army Minister Anami tacitly threatened a coup (“civil war”), the emperor accepted the majority view that the reply to the Potsdam declaration should include only one condition not the four urged by “Big Six.” Nevertheless, the condition that Hirohito accepted was not the one that foreign minister Togo had brought to the conference. What was at stake was the definition of the kokutai (national policy). Togo’s proposal would have been generally consistent with a constitutional monarchy because it defined the kokutai narrowly as the emperor and the imperial household. What Hirohito accepted, however, was a proposal by the extreme nationalist Kiichiro Hiranuma which drew upon prevailing understandings of the kokutai: the “mythical notion” that the emperor was a living god. “This was the affirmation of the emperor’s theocratic powers, unencumbered by any law, based on Shinto gods in antiquity, and totally incompatible with a constitutional monarchy.” Thus, the Japanese response to the Potsdam declaration opposed “any demand which prejudices the prerogatives of his Majesty as a sovereign ruler.” This proved to be unacceptable to the Truman administration.[63]

Document 76:“Magic’ – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 508, August 10, 1945

Source: RG 457, Summaries of Intercepted Japanese Messages (“Magic” Far East Summary, March 20, 1942 – October 2, 1945), box 7, SRS 491-547

More intercepted messages on the bombing of Hiroshima.

Documents 77A-B: The First Japanese Offer Intercepted

77A. “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1233 – August 10, 1945, Top Secret Ultra

77B. Translation of intercepted Japanese messages, circa 10 August 10, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18

The first Japanese surrender offer was intercepted shortly before Tokyo broadcast it. This issue of the diplomatic summary also includes Togo’s account of his notification of the Soviet declaration of war, reports of Soviet military operations in the Far East, and intercepts of French diplomatic traffic. A full translation of the surrender offer was circulated separately. The translations differ but they convey the sticking point that prevented U.S. acceptance: Tokyo’s condition that the allies not make any “demand which prejudices the prerogatives of His Majesty as a sovereign ruler.”

Document 78: Diary Entry, Friday, August 10, 1945, Henry Wallace Diary

Source: Papers of Henry A. Wallace, Special Collections Department, University of Iowa Libraries, Iowa City, Iowa (copy courtesy of Special Collections Department)

Note: The second page of the diary entry includes a newspaper clipping of the Associated Press’s transmission of the Byrnes note. Unfortunately, AP would not authorize the Archive to reproduce this item without payment. Therefore, we are publishing an excised version of the entry, with a link to the Byrnes note.

Secretary of Commerce (and former Vice President) Henry Wallace provided a detailed report on the cabinet meeting where Truman and his advisers discussed the Japanese surrender offer, Russian moves into Manchuria, and public opinion on “hard” surrender terms. With Japan close to capitulation, Truman asserted presidential control and ordered a halt to atomic bombings. Barton J. Bernstein has suggested that Truman’s comment about “all those kids” showed his belated recognition that the bomb caused mass casualties and that the target was not purely a military one.[64]

Document 79: Entries for 10-11 August, Robert P. Meiklejohn Diary

Source: W.A. Harriman Papers, Library of Congress, box 211, Robert Pickens Meiklejohn World War II Diary At London and Moscow March 10, 1941-February 14, 1946, Volume II (Privately printed, 1980 [Printed from hand-written originals]) (Reproduced with permission)

In these entries, Meiklejohn discussed how he and others in the Moscow Embassy learned about the bombing of Nagasaki from the “OWI Bulletin.” Entries for 10 and 11 August cover discussion at the Embassy about the radio broadcast announcing that Japan would surrender as long the Emperor’s status was not affected. Harriman opined that “surrender is in the bag” because of the Potsdam Declaration’s provision that the Japanese could “choose their own form of government, which would probably include the Emperor.” Further, “the only alternative to the Emperor is Communism,” implying that an official role for the Emperor was necessary to preserve social stability and prevent social revolution.

Document 80: Stimson Diary Entries, Friday and Saturday, August 10 and 11, 1945

Source: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

Stimson’s account of the events of 10 August focused on the debate over the reply to the Japanese note, especially the question of the Emperor’s status. The U.S. reply, drafted during the course of the day, did not explicitly reject the note but suggested that any notion about the “prerogatives” of the Emperor would be superceded by the concept that all Japanese would be “Subject to the Supreme Commander of the Allied Powers.” The language was ambiguous enough to enable Japanese readers, upon Hirohito’s urging, to believe that they could decide for themselves the Emperor’s future role. Stimson accepted the language believing that a speedy reply to the Japanese would allow the United States to “get the homeland into our hands before the Russians could put in any substantial claim to occupy and help rule it.” If the note had included specific provision for a constitutional monarchy, Hasegawa argues, it would have “taken the wind out of the sails” of the military faction and Japan might have surrendered several days earlier, on August 11 or 12 instead of August 14.[65]

Document 81: Entries from Walter Brown Diary, 10-11 August 1945

Source: Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter Brown Papers, box 68, folder 13, “Transcript/Draft B

Brown recounted Byrnes’ debriefing of the 10 August White House meeting on the Japanese peace offer, an account which differed somewhat from that in the Stimson diary. According to what Byrnes told Brown, Truman, Stimson, and Leahy favored accepting the Japanese note, but Byrnes objected that the United States should “go [no] further than we were willing to go at Potsdam.” Stimson’s account of the meeting noted Byrnes’ concerns (“troubled and anxious”) about the Japanese note and implied that he (Stimson) favored accepting it, but did not picture the debate as starkly as Browns.

Document 82: General L. R. Groves to Chief of Staff George C. Marshall, August 10, 1945, Top Secret

Source: George C. Marshall Papers, George C. Marshall Library, Lexington, VA (copy courtesy of Barton J. Bernstein)

While Groves was making plans for the use of a third atomic weapon sometime after 17 August, depending on the weather, Marshall’s note on this memo showed that he followed Truman’s instructions to halt nuclear strikes: “It is not to be released over Japan without express authority from the President.”

Document 83: Memorandum of Conversation, “Japanese Surrender Negotiations,” August 10, 1945, Top Secret

Source: Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 10-12, 1945

Japan’s prospective surrender was the subject of detailed discussion between Harriman, British Ambassador Kerr, and Soviet Foreign Minister Molotov during the evening of August 10 (with a follow-up meeting occurring at 2 a.m.). In the course of the conversation, Harriman received a message from Washington that included the proposed U.S. reply and a request for Soviet support of the reply. After considerable pressure from Harriman, the Soviets signed off on the reply but not before tensions surfaced over the control of Japan--whether Moscow would have a Supreme Commander there as well. This marked the beginning of a U.S.-Soviet “tug of war” over occupation arrangements for Japan.[66]

Document 84: Admiral Tagaki Diary Entry for 12 August [1945]
Source: Takashi Itoh, ed., Sokichi Takagi: Nikki to Joho [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 926-927 [Translation by Hikaru Tajima]

As various factions in the government maneuvered on how to respond to the Byrnes note, Navy Minister Yonai and Admiral Tagaki discussed the latest developments. Yonai was upset that Chief of Staff Yoshijiro Umezu and naval chief Suemu Toyada had sent the emperor a memorandum arguing that acceptance of the Brynes note would “desecrate the emperor’s dignity” and turn Japan into virtually a “slave nation.” The emperor chided Umezu and Toyoda for drawing hasty conclusions; in this he had the support of Yonai, who also dressed them down. As Yonai explained to Tagaki, he had also confronted naval vice Chief Takijiro Onishi to make sure that he obeyed any decision by the Emperor. Yonai made sure that Takagi understood his reasons for bringing the war to an end and why he believed that the atomic bomb and the Soviet declaration of war had made it easier for Japan to surrender.[67]

Document 85: Memorandum from Major General Clayton Bissell, Assistant Chief of Staff, G-2, for the Chief of Staff, “Estimate of Japanese Situation for Next 30 Days,” August 12, 1945, Top Secret

Source: National Archives, RG 165, Army Operations OPD, Executive Files 1940-1945, box 12, Exec #2

Not altogether certain that surrender was imminent, Army intelligence did not rule out the possibility that Tokyo would try to “drag out the negotiations” or reject the Byrnes proposal and continue fighting. If the Japanese decided to keep fighting, G-2 opined that “Atomic bombs will not have a decisive effect in the next 30 days.” Richard Frank has pointed out that this and other documents indicate that high level military figures remained unsure as to how close Japan really was to surrender.

Document 86: The Cabinet Meeting over the Reply to the Four Powers (August 13)

Source: Gaimusho [Ministry of Foreign Affairs], ed., Shusen Shiroku [Historical Record of the End of the War] (Tokyo: Hokuyosha, 1977-1978), vol. 5, 27-35 [Translated by Toshihiro Higuchi]

The Byrnes Note did not break the stalemate at the cabinet level. An account of the cabinet debates on August 13 prepared by Information Minister Toshiro Shimamura showed the same divisions as before; Anami and a few other ministers continued to argue that the Allies threatened the kokutai and that setting the four conditions (no occupation, etc.) did not mean that the war would continue. Nevertheless, Anami argued, “We are still left with some power to fight.” Suzuki, who was working quietly with the peace party, declared that the Allied terms were acceptable because they gave a “dim hope in the dark” of preserving the emperor. At the end of the meeting, he announced that he would report to Hirohito and ask him to make another “Sacred Judgment”. Meanwhile, junior Army officers plotted a coup to thwart the plans for surrender.[68]

Document 87: Telephone conversation transcript, General Hull and Colonel Seaman [sic] – 1325 – 13 Aug 45, Top Secret

Source: George C. Marshall Library, Lexington, VA, George C. Marshall Papers (copy courtesy of Barton J. Bernstein)

While Truman had rescinded the order to drop nuclear bombs, the war was not yet over and uncertainty about Japan’s next step motivated war planner General John E. Hull (assistant chief of staff for the War Department’s Operations Division), and one of Groves’ associates, Colonel L. E. Seeman, to continue thinking about further nuclear use and its relationship to a possible invasion of Japan. As Hull explained, “should we not concentrate on targets that will be of greatest assistance to an invasion rather than industry, morale, psychology, etc.” “Nearer the tactical use”, Seaman agreed and they discussed the tactics that could be used for beach landings. In 1991 articles, Barton Bernstein and Marc Gallicchio used this and other evidence to develop the argument that concepts of tactical nuclear weapons use first came to light at the close of World War II.[69]

Document 88: “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1236 – August 13, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18

That important elements in the Japanese Army were unwilling to surrender is evident from intercepted messages dated 12 and 13 August. Willingness to accept the “destruction of the Army and Navy” rather than surrender inspired the military coup that unfolded and failed during the night of 14 August.

Document 89: “The Second Sacred Judgment”, August 14, 1945

Source: Hiroshi [Kaian) Shimomura, Shusenki [Account of the End of the War] (Tokyo, Kamakura Bunko, [1948], 148-152 [Translated by Toshihiro Higuchi]

Frightened by the rapid movement of Soviet forces into Manchuria and worried that the army might launch a coup, the peace party set in motion a plan to persuade Hirohito to meet with the cabinet and the “Big Six” to resolve the stalemate over the response to the Allies. Japan was already a day late in responding to the Byrnes Note and Hirohito agreed to move quickly. At 10:50 a.m., he met with the leadership at the bomb shelter in his palace. This account, prepared by Director of Information Shimomura, conveys the drama of the occasion (as well as his interest in shifting the blame for the debacle to the Army). After Suzuki gave the war party--Umeda, Toyoda, and Anami--an opportunity to present their arguments against accepting the Byrnes Note, he asked the emperor to speak. Asking the leadership to accept the Note, Hirohito argued that continuing the war would reduce the nation “to ashes.” Hirohito’s language about “bearing the unbearable” and his sadness over wartime losses and suffering prefigured the language he would use in his public announcement the next day. According to Bix, “Hirohito's language helped to transform him from a war to a peace leader, from a cold, aloof monarch to a human being who cared for his people” but “what chiefly motivated him … was his desire to save a politically empowered throne with himself on it.”[70]

Hirohito said that he would make a recording of the surrender announcement so that the nation could hear it. That evening army officers tried to seize the palace and find Hirohito’s recording, but the coup failed. Early the next day, General Anami committed suicide. On the morning of August 15, Hirohito broadcast the message to the nation (although he never used the word “surrender”). A few weeks later, on September 2, 1945 Japanese representatives signed surrender documents on the USS Missouri, in Tokyo harbor.[71]

Document 90: “Magic” – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 515, August 18, 1945

Source: RG 457, Summaries of Intercepted Japanese Messages (“Magic” Far East Summary, March 20, 1942 – October 2, 1945), box 7, SRS 491-547

This summary includes an intercepted account of the destruction of Nagasaki.

XI. Confronting the Problem of Radiation Poisoning

Document 91: P.L. Henshaw and R.R. Coveyou to H.J. Curtis and K. Z. Morgan, “Death from Radiation Burns,” 24 August 1945, Confidential

Source: Department of Energy Open-Net

Two scientists at Oak Ridge’s Health Division, Henshaw and Coveyou, saw a United Press report in the Knoxville News Sentinel about radiation sickness caused by the bombings. Victims who looked healthy weakened, “for unknown reasons” and many died. Lacking direct knowledge of conditions in Hiroshima and Nagasaki, Henshaw and Coveyou had their own data on the biological effects of radiation and could make educated guesses. After reviewing the impact of various atomic bomb effects--blast, heat, flash radiation (prompt effects from gamma waves), and radiation from radioactive substances--they concluded that “it seems highly plausible that a great many persons were subjected to lethal and sub-lethal dosages of radiation in areas where direct blast effects were possibly non-lethal.” It was “probable,” therefore, that radiation “would produce increments to the death rate and “even more probable” that a “great number of cases of sub-lethal exposures to radiation have been suffered.”[72]

Document 92: Memorandum of Telephone Conversation Between General Groves and Lt. Col. Rea, Oak Ridge Hospital, 9:00 a.m., August 28, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5b

Despite the reports pouring in from Japan about radiation sickness among the victims of Hiroshima and Nagasaki, General Groves and Dr. Charles Rea, a surgeon who was head of the base hospital at Oak Ridge (and had no specialized knowledge about the biological effects of radiation) dismissed the reports as “propaganda”. Unaware of the findings of Health Division scientists, Groves and Rhea saw the injuries as nothing more than “good thermal burns.”[73]

Documents 93A-B: General Farrell Surveys the Destruction

93A. Cable CAX 51813 from USS Teton to Commander in Chief Army Forces Pacific Administration, From Farrell to Groves, September 10, 1945, Secret

93B. Cable CAX 51948 from Commander in Chief Army Forces Pacific Advance Yokohoma Japan to Commander in Chief Army Forces Pacific Administration, September 14, 1945, Secret

Source: RG 77, Tinian Files, April-December 1945, box 17, Envelope B

A month after the attacks Groves’ deputy, General Farrell, traveled to Japan to see for himself the destruction of Hiroshima and Nagasaki. His vivid account shows that senior military officials in the Manhattan Project were no longer dismissive of reports of radiation poisoning. As Farrell observed in his discussion of Hiroshima, “Summaries of Japanese reports previously sent are essentially correct, as to clinical effects from single gamma radiation dose.” Such findings dismayed Groves, who worried that the bomb would fall into a taboo category like chemical weapons, with all the fear and horror surrounding them. Thus, Groves and others would try to suppress findings about radioactive effects, although that was a losing proposition.[74]

XII. Eisenhower and McCloy’s Views on the Bombings and Atomic Weapons

Document 94: Entry for 4 October 1945, Robert P. Meiklejohn Diary

Source: W.A. Harriman Papers, Library of Congress, box 211, Robert Pickens Meiklejohn World War II Diary At London and Moscow March 10, 1941-February 14, 1946, Volume II (Privately printed, 1980 [Printed from hand-written originals]) (Reproduced with permission)

In this entry written several months later, Meiklejohn shed light on what much later became an element of the controversy over the Hiroshima-Nagasaki bombings: whether any high level civilian or military officials objected to nuclear use. Meiklejohn recounted Harriman’s visit in early October 1945 to the Frankfurt-area residence of General Dwight Eisenhower, who was finishing up his service as Commanding General, U.S. Army, European Theater. It was Meiklejohn’s birthday and during the dinner party, Eisenhower and McCloy had an interesting discussion of atomic weapons, which included comments alluding to scientists’ statements about what appears to be the H-bomb project (a 20 megaton weapon), recollection of the early fear that an atomic detonation could burn up the atmosphere, and the Navy’s reluctance to use its battleships to test atomic weapons. At the beginning of the discussion, Eisenhower made a significant statement: he “mentioned how he had hoped that the war might have ended without our having to use the atomic bomb.” The general implication was that prior to Hiroshima-Nagasaki, he had wanted to avoid using the bomb.

Some may associate this statement with one that Eisenhower later recalled making to Stimson. In his 1948 memoirs (further amplified in his 1963 memoirs), Eisenhower claimed that he had “expressed the hope [to Stimson] that we would never have to use such a thing against an enemy because I disliked seeing the United States take the lead in introducing into war something as horrible and destructive as this new weapon was described to be.” That language may reflect the underlying thinking behind Eisenhower’s statement during the dinner party, but whether Eisenhower used such language when speaking with Stimson has been a matter of controversy. In later years, those who knew both thought it unlikely that the general would have expressed misgivings about using the bomb to a civilian superior. Eisenhower’s son John cast doubts about the memoir statements, although he attested that when the general first learned about the bomb he was downcast.

Stimson’s diary mentions meetings with Eisenhower twice in the weeks before Hiroshima, but without any mention of a dissenting Eisenhower statement (and Stimson’s diaries are quite detailed on atomic matters). The entry from Meiklejohn’s diary does not prove or disprove Eisenhower’s recollection, but it does confirm that he had doubts which he expressed only a few months after the bombings. Whether Eisenhower expressed such reservations prior to Hiroshima will remain a matter of controversy.[75]

The editor thanks Barton J. Bernstein, J. Samuel Walker, Gar Alperovitz, David Holloway, and Alex Wellerstein for their advice and assistance, and Tsuyoshi Hasegawa for kindly providing copies of some of the Japanese sources that were translated for this compilation. Hasegawa’s book, Racing the Enemy: Stalin, Truman, and the Surrender of Japan (Cambridge, Harvard University Press, 2005), includes invaluable information on Japanese sources. David Clark, an archivist at the Harry S. Truman Library, and James Cross, Manuscripts Archivist at Clemson University Library’s Special Collections, kindly provided material from their collections. The editor also thanks Kyle Hammond and Gregory Graves for research assistance and Toshihiro Higuchi and Hikaru Tajima (who then were graduate students in history at Georgetown University and the University of Tokyo respectively), for translating documents and answering questions on the Japanese sources. The editor thanks Anna Melyakova (National Security Archive) for translating Russian language material.

Notes

[1]. The World Wide Web includes significant documentary resources on these events. The Truman Library has published a helpful collection of archival documents, some of which are included in the present collection, see http://www.trumanlibrary.org/whistlestop/study_collections/bomb/large/index.php. A collection of transcribed documents is Gene Dannen’s “Atomic Bomb: Decision.” For a print collection of documents, see Dennis Merrill ed., Documentary History of the Truman Presidency: Volume I: The Decision to Drop the Atomic Bomb on Japan (University Publications of America, 1995). A more recent collection of documents, along with a bibliography, narrative, and chronology, is Michael Kort’s The Columbia Guide to Hiroshima and the Bomb (New York: Columbia University Press, 2007). An important on-line collection focuses on the air-raids of Japanese cities and bases, providing valuable context for the atomic attacks.

[2]. For the early criticisms and their impact on Stimson and other former officials, see Barton J. Bernstein, “Seizing the Contested Terrain of Early Nuclear History: Stimson, Conant, and Their Allies Explain the Decision to Use the Atomic Bomb,” Diplomatic History 17 (1993): 35-72, and James Hershberg, James B. Conant: Harvard to Hiroshima and the Making of the Nuclear Age (Stanford, Stanford University Press, 1995), 291-301.

For Stimson’s article, see “The Decision to Use the Atomic Bomb,” Harper’s 194 (February 1947): 97-107. Social critic Dwight MacDonald published trenchant criticisms immediately after Hiroshima-Nagasaki; see Politics Past: Essays in Political Criticism (New York: Viking, 1972), 169-180.

[3] . The proposed script for the Smithsonian exhibition can be seen at Philipe Nobile,

Judgment at the Smithsonian (New York: Matthews and Company, 1995), pp. 1-127. For reviews of the controversy, see Barton J. Bernstein, “The Struggle Over History: Defining the Hiroshima Narrative,” ibid., 128-256, and Charles T. O’Reilly and William A. Rooney, The Enola Gay and The Smithsonian (Jefferson, NC: McFarland and Company, 2005).

[4] . For the extensive literature, see the references in J. Samuel Walker, Prompt and Utter Destruction: Truman and the Use of Atomic Bombs against Japan (Chapel Hill: University of North Carolina Press, 2004) at 131-136, as well as Walker’s latest contribution, “Recent Literature on Truman’s Atomic Bomb Decision: A Search for Middle Ground,” Diplomatic History 29 (April 2005): 311-334. For more recent contributions, see Sean Malloy, Atomic Tragedy: Henry L. Stimson and the Decision to Use the Bomb Against Japan (Ithaca: Cornell University Press, 2008), Andrew Rotter, Hiroshima: The World's Bomb (New York: Oxford, 2008), Campbell Craig and Sergey Radchenko, The Atomic Bomb and the Origins of the Cold War (New Haven, Yale University Press, 2008), Wilson D. Miscamble, The Most Controversial Decision: Truman, the Atomic Bombs, and the Defeat of Japan (New York: Cambridge University Press, 2011). Also important to take into account is John Dower’s extensive discussion of Hiroshima/Nagasaki in context of the U.S. fire-bombings of Japanese cities in Cultures of War: Pearl Harbor/Hiroshima/9-11/Iraq (New York, W. Norton, 2010), 163-285.

[5] . The editor particularly benefited from the source material cited in the following works: Robert S. Norris, Racing for the Bomb: General Leslie S. Groves, The Manhattan Project’s Indispensable Man (South Royalton, VT: Steerforth Press, 2002); Gar Alperovitz, The Decision to Use the Bomb and the Architecture of an American Myth (New York: Alfred E. Knopf, 1995); Richard B. Frank, Downfall: The End of the Imperial Japanese Empire (New York: Random House, 1999), Martin Sherwin, A World Destroyed: Hiroshima and the Origins of the Arm Race (New York, Vintage Books, 1987), and as already mentioned, Hasegawa’s Racing the Enemy: Stalin, Truman, and the Surrender of Japan (Cambridge, Harvard University Press, 2005). Barton J. Bernstein’s numerous articles in scholarly publications (many of them are listed in Walker’s assessments of the literature) constitute an invaluable guide to primary sources. An article that Bernstein published in 1995, “The Atomic Bombings Reconsidered,” Foreign Affairs 74 (1995), 135-152, nicely summarizes his thinking on the key issues.

[6] . Malloy (2008), 49-50. For more on the Uranium Committee, the decision to establish the S-1 Committee, and the overall context, see James G. Hershberg, James B. Conant: Harvard to Hiroshima and the Making of the Nuclear Age (Stanford, Stanford University Press, 1995), 140-154.

[7] . Sean Malloy, “`A Very Pleasant Way to Die’: Radiation Effects and the Decision to Use the Atomic Bomb against Japan,” Diplomatic History 36 (2012), especially 523. For an important study of how contemporary officials and scientists looked at the atomic bomb prior to first use in Japan, see Michael D. Gordin, Five Days in August: How World War II Became a Nuclear War (Princeton: Princeton University Press, 2007).

[8] . Norris, 169.

[9] . Malloy (2008), 57-58.

[10] . See also Norris, 362.

[11] . For discussion of the importance of this memorandum, see Sherwin, 126-127, and Hershberg, James B. Conant, 203-207.

[12] . Alperovitz, 662; Bernstein (1995), 139; Norris, 377.

[13]. Quotation and statistics from Thomas R. Searle, “`It Made a Lot of Sense to Kill Skilled Workers’: The Firebombing of Tokyo in March 1945, The Journal of Military History 55 (2002):103. More statistics and a detailed account of the raid is in Ronald Schaffer, Wings of Judgment: American Bombing in World War II (New York: Oxford University Press, 1985), 130-137.

[14]. Searle, “`It Made a Lot of Sense to Kill Skilled Workers,’” 118. For detailed background on the Army Air Force’s incendiary bombing planning, see Schaffer (1985) 107-127. On Stimson, see Schaffer (1985), 179-180 and Malloy (2008), 54.

[15] . See for example, Bernstein (1995), 140-141.

[16] . For useful discussion of this meeting and the other Target Committee meetings, see Norris, 382-386.

[17] . Malloy, “A Very Pleasant Way to Die,” 531-534.

[18] . Schaffer, Wings of Judgment, 143-146.

[19] . Alperovitz argues that the possibility of atomic diplomacy was central to the thinking of Truman and his advisers, while Bernstein, who argues that Truman’s primary objective was to end the quickly, suggests that the ability to “cow other nations, notably the Soviet Union” was a “bonus” effect. See Bernstein (1995), 142.

[20] . Alperovitz, 147; Robert James Maddox, Weapons for Victory: The Hiroshima Decision Fifty Years Later (Columbia: University of Missouri Press, 1995), 52; Gabiel Kolko, The Politics of War: The World and United States Foreign Policy, 1943-1945 (New York: Pantheon Books, 1990), 421-422. As Alperovitz notes, the Davies papers include variant diary entries and it is difficult to know which are the most accurate.

[21] . Malloy (2008), 112

[22] . Bernstein (1995), 146.

[23] . Bernstein (1995), 144. See also Malloy (2008), at 116-117, including the argument that 1) Stimson was deceiving himself by accepting the notion that a “vital war plant …surrounded by workers’ houses” was a legitimate military target, and 2) that Groves was misleading Stimson by withholding the Target Committee’s conclusions that the target would be a city center.

[24] . Walker (2005), 320.

[25] . Frank Costigliola, France and the United States: The Cold Alliance Since World War II (New York, Twayne, 1992), 38-39.

[26] . Barton J. Bernstein, Introduction to Helen S. Hawkins et al. editors, Toward a Livable World: Leo Szilard and the Crusade for Nuclear Arms Control (Cambridge: MIT Press, 1987), xxx-xxv; Sherwin, 210-215.

[27] . Herbert P. Bix, Hirohito and the Making of Modern Japan (New York: HarperCollins Publishers, 2000), 523.

[28] . Walker (2005), 319-320.

[29] . For a recent review of the debate on casualty estimates, see Walker (2005), 315, 317-318, 321, 323, and 324-325.

[30] . Hasegawa, 105; Alperovitz, 67-72; Forrest Pogue, George C. Marshall: Statesman, 1945-1959 (New York: Viking, 1987), 18. Pogue only cites the JCS transcript of the meeting; presumably, an interview with a participant was the source of the McCloy quote.

[31] . Alperovitz, 226; Bernstein, “Understanding the Atomic Bomb and the Japanese Surrender,” Diplomatic History 19 (1995), 237, note 22.

[32]. Malloy (2008), 123-124.

[33] . Alperovitz, 242, 245; Frank, 219.

[34] . Malloy (2008), 125-127.

[35] . Bernstein, introduction, Toward a Livable World, xxxvii-xxxviii.

[36] . “Magic” summaries for post-August 1945 remain classified at the National Security Agency. Information from the late John Taylor, National Archives. For background on Magic and the “Purple” code, see John Prados, Combined Fleet Decoded: The Secret History of American Intelligence and the Japanese Navy in World War II ( New York: Random House, 1995), 161-172 and David Kahn, The Codebreakers: The Story of Secret Writing (New York: Scribner, 1996), 1-67.

[37] . Alperovitz, 232-238.

[38] . Maddox, 83-84; Hasegawa, 126-128. See also Walker (2005), 316-317.

[39] . Hasegawa, 28, 121-122.

[40] . Peter Grose, Gentleman Spy: The Life of Allen Dulles (Boston: Houghton Mifflin, 1994), 170-174, 248-249.

[41] . David Holloway, “Barbarossa and the Bomb: Two Cases of Soviet Intelligence in World War II,” in Jonathan Haslam and Karina Urbach, eds., Secret Intelligence in the European States System, 1918-1989 (Stanford: Stanford University Press, 2014), 63-64. For the inception of the Soviet nuclear program and the role of espionage in facilitating it, see Holloway, Stalin and the Bomb (New Haven, Yale University Press, 1994).

[42] . For the distances, see Norris, 407.

[43] . For on-line resources on the first atomic test, see www.trinityremembered.com/

[44] . Bernstein’s detailed commentary on Truman’s diary has not been reproduced here except for the opening pages where he provides context and background.

[45] . Frank, 258; Bernstein (1995), 147; Walker (2005), 322. See also Alex Wellerstein’s “The Kyoto Misconception

[46] . Maddox, 102; Alperovitz, 269-270; Hasegawa, 152-153.

[47] . Hasegawa, 292.

[48]. Bernstein, “Understanding the Atomic Bomb and the Japanese Surrender,” Diplomatic History 19 (1995), 146-147; Alperovitz, 415; Frank, 246.

[49] . Alperovitz, 392; Frank, 148.

[50] . Alperovitz, 281-282. For Davies at Potsdam, see Elizabeth Kimball MacLean, Joseph E. Davies: Envoy to the Soviets (Westport, CT: Praeger, 1992), 151-166

[51]. Hasegawa, 168; Bix, 518.

[52]. Bix, 490, 521.

[53] . Alperovitz, 415; Frank, 246.

[54] . Frank, 273-274; Bernstein, “The Alarming Japanese Buildup on Southern Kyushu, Growing U.S. Fears and Counterfactual Analysis: Would the Planned November 1945 Invasion of Southern Kyushu Have Occurred?” Pacific Historical Review 68 (1999): 561-609.

[55] . Maddox, 105.

[56] . Barton J. Bernstein, "'Reconsidering the 'Atomic General': Leslie R. Groves," The Journal of Military History 67 (July 2003): 883-920. See also Malloy, “A Very Pleasant Way to Die,” 539-540.

[57] . For casualty figures and the experience of people on the ground, see Frank, 264-268 and 285-286, among many other sources. Drawing on contemporary documents and journals, Masuji Ibuse’s novel Black Rain (Tokyo, Kodansha, 1982) provides an unforgettable account of the bombing and its aftermath. For early U.S. planning to detonate the weapon at a height designed to maximize destruction from mass fires and other effects, see Alex Wellerstein, “The Height of the Bomb.”

[58] . Sadao Asada, “The Shock of the Atomic Bomb and Japan’s Decision to Surrender: A Reconsideration,” Pacific Historical Review 67 (1998): 101-148; Bix, 523; Frank, 348; Hasegawa, 298. Bix appears to have moved toward a position close to Hasegawa’s; see Bix, “Japan's Surrender Decision and the Monarchy: Staying the Course in an Unwinnable War,” Japan Focus . For emphasis on the “shock” of the atomic bomb, see also Lawrence Freedman and Saki Dockrill, “Hiroshima: A Strategy of Shock,” in Saki Dockrill, ed., From Pearl Harbor to Hiroshima : the Second World War in Asia and the Pacific, 1941-1945 (New York, St. Martin’s Press, 1994), 191-214. For more on the debate over Japan’s surrender, see Hasegawa’s important edited book, The End of the Pacific War: A Reappraisal (Stanford: Stanford University Press, 2007), with major contributions by Hasegawa, Holloway, Bernstein, and Hatano.

[59] . Melvyn P. Leffler, “Adherence to Agreements: Yalta and the Experiences of the Early Cold War,” International Security 11 (1986): 107; Holloway, “Barbarossa and the Bomb,” 65.

[59a] For more on these developments, see Asada, "The Shock of the Atomic Bomb and Japan's Decision to Surrender: A Reconsideration," 486-488.

[60] . Hasegawa, 191-192.

[61]. Frank, 286-287; Sherwin, 233-237; Bernstein (1995), 150; Maddox, 148.

[62] . The Supreme War Council comprised the prime minister, foreign minister, army and navy ministers, and army and navy chiefs of staff; see Hasegawa, 72.

[63] . For the maneuverings on August 9 and the role of the kokutai, see Hasegawa, 3-4, 205-214

[64] . For Truman’s recognition of mass civilian casualties, see also his letter to Senator Richard Russell, 9 August 1945.

[65] . Hasegawa, 295.

[66] . For “tug of war,” see Hasegawa, 226-227.

[67] . Hasegawa, 228-229, 232.

[68] . Hasegawa, 235-238.

[69] . Barton J. Bernstein, “Eclipsed by Hiroshima and Nagasaki: Early Thinking about Tactical Nuclear Weapons,” International Security 15 (Spring 1991): 149-173; Marc Gallicchio, “After Nagasaki: General Marshall’s Plans for Tactical Nuclear Weapons in Japan,” Prologue 23 (Winter 1991): 396-404. Letters from Robert Messer and Gar Alperovitz, with Bernstein’s response, provide insight into some of the interpretative issues. “Correspondence,” International Security 16 (Winter 1991/1992): 214-221.

[70] . Bix, “Japan's Surrender Decision and the Monarchy: Staying the Course in an Unwinnable War,” Japan Focus.

[71]. Hasegawa, 238-249, 285. Translations of Hirohito’s speech are available; so is the actual broadcast.

[72] . See Malloy, “A Very Pleasant Way to Die,” 541-542.

[73]. For Groves and the problem of radiation sickness, see Norris, 339-441, Bernstein, “Reconsidering the ‘Atomic General’: Leslie R. Groves,” Journal of Military History 67 (2003), 907-908, and Malloy, “A Very Pleasant Way to Die,” 513-518 and 539-542

[74] See Janet Farrell Brodie, “Radiation Secrecy and Censorship after Hiroshima and Nagasaki,” The Journal of Social History 48 (2015): 842-864.

[75]. For Eisenhower’s statements, see Crusade in Europe (Garden City: Doubleday, 1948), 443, and Mandate for Change (Garden City: Doubleday, 1963), 312-313. Barton J. Bernstein’s 1987 article, “Ike and Hiroshima: Did He Oppose It?” The Journal of Strategic Studies 10 (1987): 377-389, makes a case against relying on Eisenhower’s memoirs and points to relevant circumstantial evidence. For a slightly different perspective, see Malloy (2007), 138