What was the recorded radio address announcing Japan’s surrender called?

The recorded radio address announcing Japan’s surrender was called the Gyokuon-hōsō.

The Japanese term is often translated as “Jewel Voice Broadcast,” referring to the emperor’s voice. Hirohito recorded the speech on August 14, 1945, and it was broadcast at noon on August 15. It was the first known time ordinary Japanese people heard their emperor speak by radio.

The address announced acceptance of the Potsdam Declaration, although it did not plainly use everyday language to say that Japan had surrendered. Hirohito referred to the devastating wartime situation and the atomic bomb, and he urged the Japanese people to endure the unendurable and work toward rebuilding.

The broadcast became possible only after a recording survived an attempted military coup. Officers opposed to surrender searched the Imperial Palace and tried to stop the transmission, but the recordings were hidden and safely delivered to NHK.