One of the arguments of critics of Truman’s use of the atomic bomb, is that a demonstration could have been made of it without blood being shed, over the ocean for example, the Japanese would have seen the power of the bomb and surrendered. Well, we know that is incorrect. We know that because the Japanese did not surrender after Hiroshima. We also know that the Japanese had no intention of surrendering after Hiroshima. Discussions within the Japanese cabinet were deadlocked until the second bomb was dropped on Nagasaki, with the dominant war faction claiming that the US probably had no more atomic bombs and that their strategy of holding out, inflicting a defeat on an American land invasion, and then negotiating from strength, was the best strategy for Japan. The deadlock continued on August 9, 1945 when the atomic bombing of Nagasaki caused the war and peace factions to agree to bring their differences to the Emperor.
Lord Privy Seal Kido Koichi, the man in the Japanese government most close to the Emperor Hirohito who finally commanded surrender on August 10, 1945 when advised that the war and peace factions were still deadlocked, later estimated that the August surrender spared Japan twenty million casualties. Mitsumasa Yonai, the Japanese naval minister, but a member of the peace faction, told the Emperor that the atomic bombings and the Soviet Declaration of War, which occurred on August 9, were divine gifts that allowed Japan to surrender without seeming to capitulate to popular discontent. Absent the atomic bombings, there is zero evidence that Japan would have surrendered in August 1945. Even after the Emperor made his decision there was an attempt by factions within the Army to stage a military coup and prevent the surrender, but that is the subject of a future post.