On July 27, when the Japanese Supreme War Council met to consider Japan's response to the Potsdam Declaration, Foreign Minister Togo was still attempting to find some way to end the war with honor. He stated his opinion that the declaration did not demand Japan's unconditional surrender explicitly and therefore should be regarded as a moderation of Allied terms. The Japanese military leaders, however, were not yet prepared to consider surrender; they demanded a strong statement from the government condemning the declaration. It is a testament to Togo's fortitude and skill that, despite the vehement opposition of the militarists, he was able to persuade the council and the cabinet that Japan should await further developments before responding to the declaration, while trying to determine the intentions of the Soviet Union. Unfortunately, the next day, the Japanese press reported the government's response in a way that would challenge the most creative imagination. Domei, the semiofficial Japanese news agency, interpreted Togo's statement that the government had not yet made a decision on the Potsdam Declaration to mean that the government would ignore the declaration. When translated by American officials, the Japanese response was treated not only as a rejection of the Potsdam Declaration but as a contemptuous one at that.
While the Japanese government gave further consideration to the Potsdam Declaration, the U.S. Air Force went into action. At 2:45 in the morning of Sunday, August 6, the Enola Gay, the B-29 carrying "Little Boy," lifted off the Tinian runway. Five and one-half hours later, at 8:15 Hiroshima time, the bomb was dropped from an altitude of 31,000 feet. Forty-three seconds later it detonated 1,800 feet above the city. Aboard the Enola Cay, tailgunner George Caron described the scene from a distance of eleven miles and 29,000 feet of altitude as a "peep into hell."
...The Japanese government did not receive a complete description of the attack on Hiroshima until August 8. Lieutenant General Seijo Arisue, who headed the investigating team that flew to the city, reported: "When the plane flew over Hiroshima there was but one black dead tree, as if a crow was perched over it. There was nothing but that tree. . . . The city itself was completely wiped out." The Japanese soon realized that only an atomic bomb could produce such destruction.
Years later, it was possible to make a more complete assessment of what had happened at Hiroshima. At the hypocenter of the explosion, with a TNT equivalent of twenty kilotons, the temperature reached several million degrees centigrade. The shock wave created by the explosion was strong enough to break windows fifteen kilometers from the hypocenter. Four kilometers away, buildings ,were charred. Three kilometers away, about ninety percent of the buildings had experienced fire and blast damage. Within a two-kilometer circle, only ashes, fist-size pieces of rubble, and a few shells of reinforced concrete buildings remained. Thirteen square kilometers of the city were razed, including forty-two of the city's forty-five hospitals. Of Hiroshima's 340,000 population, 130,000 were dead by November 1945 and an additional 70,000 had died by 1950. Included among these casualties were twenty American airmen who were being held in Hiroshima as prisoners of war... Those who survived the blast had to deal with nausea, vomiting, diarrhea, weakness, and blood disorder— all symptoms of acute radiation sickness. They also had to endure the profound psychological effects of their ordeal, which included guilt that they had survived while others had not, and anxiety about their future health and the impact of radiation on their descendants. The Research Institute for Nuclear Medicine and Biology at Hiroshima University estimated that, by the mid-1950s, the risk of cancer increased 30 or 40 times the norm. An increase in stillbirths, birth defects, and infant mortality was also clear in the 70.000 pregnancies examined in the study. There is, of course, no way to measure the entire magnitude of the human suffering caused by the atomic conflagration of Hiroshima.
While the Japanese government was assessing the effects of the attack on Hiroshima, it received another shock, one that added immeasurably to the pressure toward surrender. At one hour after midnight, Tokyo time, on August 9, Soviet forces attacked the Japanese army in Manchuria... [T]he Soviet leader realized that the use of the atomic bomb on Hiroshima, coupled with what he considered the lenient terms offered in the Potsdam Declaration, made Japanese surrender only a matter of days. Any Soviet delay could bring about a Japanese capitulation before the Soviet Union received the opportunity to claim its full share of the spoils.
Ten hours after the Soviet attack, the Japanese Supreme War Council met in Tokyo. Foreign Minister Togo insisted that it was absolutely essential for Japan to comply with the Potsdam Declaration before another Japanese city was destroyed by an atomic bomb. The militarist faction, however, continued to demur. In addition to demanding the retention of the emperor after the war, the militarists insisted on two other conditions before they would accept surrender: (1) Japan would not be occupied after the war, and if that could not be obtained, Japan must be occupied only minimally; and (2) Japanese war criminals would be tried by Japanese courts. Because Togo considered the militarists' demands excessive, the meeting of the council adjourned without reaching a decision.
By this time, however, it was too late to avoid the loss of a second Japanese city. At 10:58 a.m. local time, on August 9, "Fat Man," the plutonium bomb, was dropped on Nagasaki. Ironically and tragically for that city, Nagasaki was selected as the target only after the B-29 carrying the bomb could not see Kokura, the primary target, because of dense cloud cover over that city. The second atomic attack on Japan occurred two days earlier than originally planned because poor weather was anticipated on August 11, and because the Truman administration wanted to create the impression, by a rapid follow-up to the Hiroshima attack, that the United States possessed more atomic bombs than it actually did.
The destruction of Nagasaki sealed the fate of Japan. Over the continued opposition of the militarists, who still wanted to prolong the war, the emperor decisively intervened to bring the conflict to an end. The Japanese government, on the morning of August 10, agreed to accept the terms of the Potsdam Declaration. Only one condition was attached: "that the said declaration does not comprise any demand which prejudices the prerogatives of His Majesty as Sovereign Ruler."
When President Truman assembled his advisers on the morning of August 10 to weigh the Japanese message, the question that dominated the meeting was... : Should the United States redefine unconditional surrender to permit retention of the emperor? After heated debate among the participants, Truman accepted a compromise...: the United States would agree to retention of the emperor provided that "from the moment of surrender the authority of the Emperor and the Japanese Government to rule the state shall be subject to the Supreme Commander of the Allied powers, who will take such steps as he deems proper to effectuate the surrender terms." In addition, the American reply stated: "The ultimate form of government of Japan shall, in accordance with the Potsdam Declaration, be established by the freely expressed will of the Japanese people."
On August 11, following acceptance by Britain, China and, with reluctance, the Soviet Union, the American reply was transmitted to the Japanese. Even at this late date, however, neither the cabinet nor the Supreme War Council could reach a decision on the American terms. Again the intervention of the emperor was necessary. In a short speech to his ministers on August 12, Hirohito said the American terms should be accepted. "Unless the war be brought to an end at this moment," he said. "I fear that the national polity will be destroyed, and the nation annihilated." Hirohito's ministers accepted the imperial will. During the night of August 14, Japan transmitted her decision to surrender to the United States. Truman announced the Japanese capitulation at 7:00 p.m. Washington time, the same day. On September 2, 1945 the war with Japan officially ended when the instruments of surrender were signed aboard the U.S.S. Missouri in Tokyo Bay.