Manhattan Project: Japan Surrenders, August 10-15, 1945

JAPAN SURRENDERS
(August 10-15, 1945)
Events > Dawn of the Atomic Era, 1945

Prior to the atomic attacks on Hiroshima and Nagasaki, elements existed within the Japanese government that were trying to find a way to end the war. In June and July 1945, Japan attempted to enlist the help of the Soviet Union to serve as an intermediary in negotiations. No direct communication occurred with the United States about peace talks, but American leaders knew of these maneuvers because the United States for a long time had been intercepting and decoding many internal Japanese diplomatic communications. From these intercepts, the United States learned that some within the Japanese government advocated outright surrender. A few diplomats overseas cabled home to urge just that.

From the replies these diplomats received from Tokyo, the United States learned that anything Japan might agree to would not be a surrender so much as a "negotiated peace" involving numerous conditions. These conditions probably would require, at a minimum, that the Japanese home islands remain unoccupied by foreign forces and even allow Japan to retain some of its wartime conquests in East Asia. Many within the Japanese government were extremely reluctant to discuss any concessions, which would mean that a "negotiated peace" to them would only amount to little more than a truce where the Allies agreed to stop attacking Japan. After twelve years of Japanese military aggression against China and over three and one-half years of war with the United States (begun with the surprise attack on Pearl Harbor), American leaders were reluctant to accept anything less than a complete Japanese surrender.

The one possible exception to this was the personal status of the emperor himself. Although the Allies had long been publicly demanding "unconditional surrender," in private there had been some discussion of exempting the emperor from war trials and allowing him to remain as ceremonial head of state. In the end, at Potsdam, the Allies (right) went with both a "carrot and a stick," trying to encourage those in Tokyo who advocated peace with assurances that Japan eventually would be allowed to form its own government, while combining these assurances with vague warnings of "prompt and utter destruction" if Japan did not surrender immediately. No explicit mention was made of the emperor possibly remaining as ceremonial head of state. Japan publicly rejected the Potsdam Declaration, and on July 25, 1945, President Harry S. Truman gave the order to commence atomic attacks on Japan as soon as possible.

Following the bombing of Hiroshima on August 6, 1945 (left), the Japanese government met to consider what to do next. The emperor had been urging since June that Japan find some way to end the war, but the Japanese Minister of War and the heads of both the Army and the Navy held to their position that Japan should wait and see if arbitration via the Soviet Union might still produce something less than a surrender. Military leaders also hoped that if they could hold out until the ground invasion of Japan began, they would be able to inflict so many casualties on the Allies that Japan still might win some sort of negotiated settlement. Next came the virtually simultaneous arrival of news of the Soviet declaration of war on Japan of August 8, 1945, and the atomic bombing of Nagasaki of the following day. Another Imperial Council was held the night of August 9-10, and this time the vote on surrender was a tie, 3-to-3. For the first time in a generation, the emperor (right) stepped forward from his normally ceremonial-only role and personally broke the tie, ordering Japan to surrender. On August 10, 1945, Japan offered to surrender to the Allies, the only condition being that the emperor be allowed to remain the nominal head of state.

Planning for the use of additional nuclear weapons continued even as these deliberations were ongoing. On August 10, Leslie Groves reported to the War Department that the next bomb, another plutonium implosion weapon, would be "ready for delivery on the first suitable weather after 17 or 18 August." Following the destruction of Hiroshima and Nagasaki, only two targets remained from the original list: Kokura Arsenal and the city of Niigata. Groves therefore requested that additional targets be added to the target list. His deputy, General Kenneth Nichols, suggested Tokyo. Truman, however, ordered an immediate halt to atomic attacks while surrender negotiations were ongoing. As the Secretary of Commerce Henry Wallace recorded in his diary, Truman remarked that he did not like the idea of killing "all those kids."

On August 12, the United States announced that it would accept the Japanese surrender, making clear in its statement that the emperor could remain in a purely ceremonial capacity only. Debate raged within the Japanese government over whether to accept the American terms or fight on. Meanwhile, American leaders were growing impatient, and on August 13 conventional air raids resumed on Japan. Thousands more Japanese civilians died while their leaders delayed. The Japanese people learned of the surrender negotiations for the first time when, on August 14, B-29s showered Tokyo with thousands of leaflets containing translated copies of the American reply of August 12. Later that day, the emperor called another meeting of his cabinet and instructed them to accept the Allied terms immediately, explaining "I cannot endure the thought of letting my people suffer any longer"; if the war did not end "the whole nation would be reduced to ashes."

The only question remaining now was if Japan's military leaders would allow the emperor to surrender. Loyalty to the emperor was an absolute in the Japanese military, but so was the refusal to surrender, and now that the two had come into conflict, open rebellion was a possible result. The emperor recorded a message in which he personally accepted the Allied surrender terms, to be broadcast over Japanese radio the following day. This way everyone in Japan would know that surrender was the emperor's personal will. Some within the Japanese military actually attempted to steal this recording before it could be broadcast, while others attempted a more general military coup in order to seize power and continue the war. Other elements of the Japanese military remained loyal to the emperor. The Minister of War, General Anami Korechika, personally supported continuing the war, but he also could not bring himself to openly rebel against his emperor. The strength of his dilemma was such that he opted for suicide as the only honorable way out. In the end, his refusal to assist the coup plotters was instrumental in their defeat by elements within the military that remained loyal to the emperor.

On August 15, 1945, the emperor's broadcast announcing Japan's surrender was heard via radio all over Japan. For most of his subjects, it was the first time that they had ever heard his voice. The emperor explained that "the war situation has developed not necessarily to Japan's advantage," and that "the enemy has begun to employ a new and most cruel bomb." Over the next few weeks, Japan and the United States worked out the details of the surrender, and on September 2, 1945, the formal surrender ceremony took place on the deck of the U.S.S. Missouri.

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Sources and notes for this page.

The text for this page is original to the Department of Energy's Office of History and Heritage Resources. The surrender negotiations are detailed in Gerhard L. Weinberg, A World at Arms: A Global History of World War II (New York: Cambridge University Press, 1994), 886-893. On the availability of the next plutonium bomb by August 17 or 18, see the memorandum, Leslie Groves to George Marshall, August 10, 1945, which is in Groves's file of "Top Secret" MED Correspondence, 1942-1946 (available from the National Archives (NARA) on microfilm M1109). For Groves's request for additional targets and Kenneth Nichols's suggestion that Tokyo be added to the target list, see Groves to General Henry "Hap" Arnold, August 10, 1945, which is also in Groves's "Top Secret" MED correspondence. The photographs of the U.S.S. Missouri during the surrender ceremony and of the B-29s are courtesy NARA. The photograph of the Potsdam conference is courtesy the Truman Presidential Library. The photograph of the mushroom cloud over Hiroshima is courtesy the United States Air Force (USAF) (via NARA). The portrait of Emperor Hirohito is courtesy the United States Army Signal Corps (via the Library of Congress (LOC)). The photograph of Fat Man is courtesy the U.S. Army Corps of Engineers (via NARA). The photograph of the Japanese soldiers on Guam is courtesy the LOC.

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