Emperor Hirohito announced Japan’s acceptance of the Potsdam Declaration in a recorded radio address on August 15, 1945.
The broadcast became known as the Jewel Voice Broadcast, or Gyokuon-hōsō. It was the first time most Japanese people had heard their emperor’s voice. Hirohito used formal Classical Japanese, and the poor sound quality made the message difficult for many listeners to understand.
The speech did not simply use the modern phrase “Japan surrenders.” Instead, Hirohito said that Japan had accepted the Allied declaration and referred to the terrible destructive power of a new bomb. A radio announcer clarified the practical meaning afterward.
The recording was made on August 14 and preserved during an attempted military coup inside the Imperial Palace. The broadcast preceded the formal signing on September 2, so August 15 and September 2 represent different milestones in Japan’s surrender. In the United States, President Harry Truman announced the surrender to the American public on August 14 Washington time.