Did the U.S. plan to drop more than two atomic bombs on Japan?

During that time, the question of how the next atomic bomb would be used was a real one.One of the most persistent claims about the end of World War II is that the United States had no more atomic bombs after the second attack and that President Harry Truman was bluffing when he promised to drop more on Japan if it did not unconditionally surrender. Just hours before hearing of Japan’s final surrender on August 14, 1945, Truman had ruefully told a British diplomat that he had “no alternative” but to order a third atomic bomb attack. The most sensitive work was conductedat a third major site: the top secret laboratory at “Site Y” in Los Alamos, New Mexico, where the bombs were designed and also close to the Trinity test site in the desert.Assembling the BombResearch facilityRaw materialsComponent manufacturingMajor siteCHRISTINA SHINTANI, NGM STAFFSOURCE: ALEX WELLERSTEINThe Manhattan ProjectThe assembly line for the atomic bombs was spread out over a great distance. The most sensitive work was conducted at a third major site: the laboratory at “Site Y” in Los Alamos, New Mexico, close to the Trinity test site in the desert.Assembling the BombResearch facilityRaw materialsComponent manufacturingMajor siteCHRISTINA SHINTANI, NGM STAFFSOURCE: ALEX WELLERSTEINThe Manhattan ProjectThe assembly line for the atomic bombs was spread out over a great distance. The most sensitive work was conducted at a third major site: the laboratory at “Site Y” in Los Alamos, New Mexico, close to the Trinity test site in the desert.Assembling the BombResearch facilityRaw materialsComponent manufacturingMajor siteCHRISTINA SHINTANI, NGM STAFF.SOURCE: ALEX WELLERSTEINThe Manhattan ProjectThe assembly line for the atomic bombs was spread out over a great distance. Firebombed citiesMarch - August 1945Preliminary candidates for atomic strikeApril 1945Revised candidates for atomic strikeMay 1945Final targets for the atomic bombJuly 1945Atomic bomb attacks: Hiroshima, August 6, 1945Nagasaki, August 9, 1945Bombing of Hiroshimaand NagasakiU.S. officials spent the spring months were assessing potential targets for atomic bomb strikes. He was overjoyed at its success, announcing that it was “the greatest thing in history.” The news of the atomic bomb was almost immediately released to the press, and a radio announcement was broadcast to Japan itself.The Japanese military knew that Hiroshima had come under some kind of major attack on August 6, but did not know its special nature. A top Japanese nuclear physicist, Professor Yoshio Nishina, reported back from Hiroshima on August 8 that there were “almost no buildings left standing,” and that, from what he could tell, “the so-called new type bomb is actually an atomic bomb.”As the Japanese were confirming what happened in Hiroshima, the next bombing mission was already beginning. (Pictures of Hiroshima and Nagasaki show the destructive power of atomic bombs.)Truman was informed of this, and his response was immediate. As Marshall wrote back to Groves: “It is not to be released over Japan without express authority from the President.” Truman may have had a very peripheral role in the ordering of the use of the atomic bomb—his main role, as Groves later put it, was not to interfere with plans already in motion—but he played a direct role in the stopping of the use of further bombs.Why did Truman, who had proclaimed the Hiroshima attack to be “the greatest thing in history,” suddenly order the stoppage? Speculation in the American press and military was rampant about if and where more atomic bombs would fall.After being told not to use the bomb, Groves called Oppenheimer in New Mexico the next day and told him not to ship the next plutonium core to Tinian. In the same discussion, though, Oppenheimer told Groves that he could report on their progress on a new weapon design, a “composite” implosion bomb that would use both plutonium and enriched uranium in one bomb, allowing them to improve their production rate dramatically.Even though Truman had put a hold on atomic bombing, the leaders of the U.S. Army Air Forces still thought that more bombs would be needed. Curtis LeMay, architect of the firebombing campaigns, put forward an urgent request to install facilities capable of assembling atomic bombs at Okinawa, perhaps anticipating the use of the weapon for the invasion of Japan.On August 13, Secretary of War Stimson indicated that perhaps the “shipments” of nuclear materials to Tinian should resume. Groves was told that the decision about whether to use another atomic bomb would be made the next day.Later that afternoon, Truman met with the British ambassador and “remarked sadly” that since the Japanese seemed unwilling to surrender unconditionally, “he now had no alternative but to order an atomic bomb to be dropped on Tokyo.” If he made the order, the operation would have taken place within days.But fortunately, it did not come to that.