Emperor Hirohito announced Japan’s surrender in his Gyokuon-hōsō radio broadcast on August 15, 1945.
The broadcast accepted the terms of the Potsdam Declaration and told the Japanese people that the war situation had developed unfavorably. It was the first time many Japanese listeners had heard the emperor’s voice.
August 15 is commonly called Victory over Japan Day, or V-J Day, especially in Japan and several Allied countries. However, the formal surrender ceremony did not occur until September 2, when Japanese representatives signed the Instrument of Surrender aboard USS Missouri in Tokyo Bay.
The distinction between August 15 and September 2 causes frequent confusion. August 15 marks the public announcement and Japan’s acceptance in principle; September 2 marks the legal and ceremonial signing that formally ended the war.