Emperor Hirohito's August 15, 1945 radio address announcing Japan's acceptance of surrender terms was the Jewel Voice Broadcast.
The Japanese name, Gyokuon-hōsō, refers to a broadcast of the emperor's voice. Hirohito recorded the rescript on August 14, and the recording was transmitted by NHK at noon the next day. It announced Japan's decision to accept the Potsdam Declaration and end the war, following the atomic bombings and the Soviet declaration of war.
The broadcast was historically unusual because ordinary Japanese people had rarely, if ever, heard the emperor speak. Hirohito used formal Classical Japanese, which was difficult for many listeners to understand. He also did not state the surrender in the plain, direct wording that audiences might have expected.
A palace coup attempt by officers opposed to surrender threatened the recording before transmission. NHK engineers helped preserve it until the broadcast went ahead. “Jewel Voice Broadcast” is a later English rendering of Gyokuon-hōsō; the Japanese term literally evokes the emperor's precious or jewel-like voice.