Emperor Hirohito’s 1945 surrender broadcast was called the Gyokuon-hōsō.
The Japanese term literally means “broadcast in the Emperor’s voice.” It refers to Hirohito’s radio address transmitted on August 15, 1945, in which he announced that Japan had accepted the terms of the Potsdam Declaration and would end the war.
The recording had been made the previous day. Hirohito used highly formal court language rather than ordinary conversational Japanese, and the audio quality was weak. As a result, many listeners could not understand every word immediately. Officials and news organizations soon explained that the speech meant Japan had surrendered.
The Gyokuon-hōsō was the first time most Japanese people had heard their emperor speak. It should not be confused with the Japanese Instrument of Surrender, which was a written document signed by Japanese and Allied representatives on September 2.