Japan first notified the Allies of its intention to surrender on August 10, 1945.
The Japanese government sent the notification through Swiss diplomatic channels, expressing willingness to accept the Potsdam Declaration while asking that the status of Emperor Hirohito be preserved. This message followed the atomic bombing of Hiroshima, the Soviet declaration of war, and the invasion of Japanese-held Manchuria.
The August 10 communication was not the same as Japan’s public surrender announcement. Emperor Hirohito’s recorded radio address was broadcast to the Japanese people on 15 August, while the formal Instrument of Surrender was signed aboard USS Missouri on 2 September.
Japan’s leaders still debated the terms after the initial message. The Allies replied that the Emperor would remain subject to the authority of the Supreme Commander for the Allied Powers. After further discussion and a failed military coup attempt, Hirohito accepted the decision and recorded the broadcast that announced the surrender. The sequence explains why several different dates are associated with Japan’s capitulation.