Japan announced its surrender on August 15, 1945, the date commonly observed as V-J Day in Japan.
Emperor Hirohito announced Japan’s acceptance of the Allied terms in a recorded radio address broadcast at noon Japan Standard Time. The announcement followed Japan’s decision to accept the Potsdam Declaration, which demanded the unconditional surrender of Japanese armed forces.
The date can be confusing because the surrender process had several important milestones. Japan notified the Allies of its acceptance on August 10, and the formal surrender document was signed aboard USS Missouri on September 2. In the United States, the announcement occurred on August 14 because of the international date line and time-zone differences.
The broadcast marked the collapse of Japan’s wartime government position, but fighting and localized military operations did not stop everywhere instantly. Formal surrender documents were still signed by Japanese commanders in different regions afterward. The date is therefore best understood as the announcement day, rather than the moment every Japanese unit ceased resistance.