The Soviet Union, in accordance with the Potsdam Agreement, declared war on Japan. According to several historians (e.g., Tsuyoshi Hasegawa, Gar Alperowitz), it was this, and not the atomic bombings of Hiroshima and Nagasaki, that prompted Japan’s unconditional surrender to the Americans. In the eyes of the Japanese military and imperial leadership, who were also poorly informed about the true extent of the bombings, the loss of two more cities did not necessarily make a difference.
