For some who are accustomed to the popular beliefs about this matter, this study may be discomforting, although that is not its intent. But if we learn from past occurrences, it may make our future decision-making abilities more capable of saving the lives of our soldiers and sailors and of people on all sides.
The Tide Turns
As the war with Germany drew closer to the end, the Allies waged an increasingly effective war against Japan. After the fall of the Mariana Islands, including Saipan, to the U.S. in July of 1944, the impending defeat of Japan became increasingly apparent to many Allied and Japanese leaders.
The Marianas had been a key area within Japan's defense perimeter; now Japan would be within range of bombing runs from Pacific Ocean locations that were superior to the China bases that had been used for bombing missions (Akira Iriye, Power and Culture: The Japanese-American War, 1941-1945, pg. 174; Michael Sherry, The Rise of American Air Power, pg. 176).
And so from November 1944 onward, Japan was the subject of numerous large-scale B-29 non-nuclear bombing raids (Robert Butow, Japan's Decision To Surrender, pg. 41). When Air Force chief General Hap Arnold asked in June 1945 when the war was going to end, the commander of the B-29 raids, General Curtis LeMay, told him September or October 1945, because by then they would have run out of industrial targets to bomb (Sherry, pg. 300 & 410(143n)).
While Japan was being bombarded from the sky, a Naval blockade was strangling Japan's ability to import oil and other vital materials and its ability to produce war materials (Barton Bernstein, ed., The Atomic Bomb, pg. 54). Admiral William Leahy, the Chief of Staff to President Roosevelt and then to President Truman, wrote, "By the beginning of September , Japan was almost completely defeated through a practically complete sea and air blockade." (William Leahy, I Was There, pg. 259).
Then in May of 1945 the surrender of Germany freed the Allies to focus their troops and resources on defeating the final enemy, Japan.
Although fighting fanatically, Japan had lost a string of high-casualty battles (U.S. Dept. of State, Foreign Relations of the U.S., The Conference of Berlin (Potsdam) 1945, vol. 1, pg. 905).
The Potsdam Proclamation
On the evening of July 26, 1945 in San Francisco (which in Tokyo was the morning of July 27) a message from the Allies now commonly known as the Potsdam Proclamation was broadcast in Japanese. The broadcast was relayed to the Japanese government on the morning of the 27th (Pacific War Research Society, The Day Man Lost, pg. 211-212).
The proclamation demanded "the unconditional surrender of all the Japanese armed forces" (U.S. Dept. of State, Foreign Relations of the U.S., The Conference of Berlin (Potsdam), vol. 2, pg. 1474-1476). It made no mention of Japan's central surrender consideration: the retention of the Emperor's position (Butow, pg. 138-139). What made this crucial was that the Japanese believed their Emperor to be a god, the heart of the Japanese people and culture (Pacific War Research Society, Japan's Longest Day, pg. 20). The absence of any assurance regarding the Emperor's fate became Japan's chief objection to the Potsdam Proclamation (Pacific War Research Society, The Day Man Lost, pg. 212-214). In addition, the proclamation made statements that, to the Japanese, could appear threatening to...