The attempted Japanese military coup on the night before the surrender broadcast was the Kyūjō incident.
The Kyūjō incident was an unsuccessful coup attempt by Japanese military officers in the early hours of 15 August 1945. The plotters tried to prevent Emperor Hirohito’s recorded surrender speech from being broadcast. They occupied parts of the Imperial Palace and searched for the recording, but they failed to find and destroy it.
The coup collapsed after senior officers refused to support it and palace officials resisted the plotters. The recorded message was broadcast at noon on 15 August, announcing Japan’s acceptance of the Allied terms. The attempted coup therefore did not stop the Emperor’s surrender announcement.
The event illustrates how divided Japan’s leadership remained even after the government had decided to accept the Potsdam Declaration. Some officers wanted to continue the war, while the Emperor and other leaders judged further resistance impossible. The formal surrender document was signed on 2 September.