Marching Orders: The Untold Story of How the American Breaking of the Japanese Secret Codes Led to the Defeat of Nazi Germany and Japan

by Bruce Lee

As it was, however, a new and uncertain President Harry S. Truman was faced with the fact, in the short period of time that the atomic bomb was first tested successfully on July 16, 1945, and the time the first bomb was dropped on Hiroshima on August 6, 1945, that Japan had not agreed to the Allied demand for unconditional surrender. Furthermore, Truman had no choice but to accept as valid the horrific casualties anticipated in an American invasion of Japan. And given the additional information gleaned from Magic/Ultra sources that (1) the Japanese had issued orders to kill all their Allied POW in the event of an invasion of Japan, and (2) the Japanese militarists had been given the approval of Emperor Hirohito to try to establish a new treaty between Japan and the Soviet Union that would divide China between the two nations, Truman was forced to use atomic weapons against Japan.