The 1945 Japanese military coup attempt that tried to stop Hirohito’s surrender broadcast was called the Kyūjō incident.
The attempted coup took place during the night of August 14–15, 1945. A group of Army officers opposed the surrender and sought to seize the Imperial Palace, prevent the emperor’s recorded message from being transmitted, and keep Japan fighting.
Major Kenji Hatanaka was one of the central organizers. The plotters searched for the recording containing Hirohito’s speech, but they failed to find it. Other senior officers did not provide the support the rebels needed, and the coup collapsed before the broadcast at noon on August 15.
The episode shows that Japan’s surrender was politically contested even after the emperor had decided to accept the Allied terms. “Kyūjō” refers to the Imperial Palace, the main site connected with the attempted seizure.