The attempted Japanese military coup that sought to stop Hirohito’s surrender broadcast was called the Kyūjō Incident. It occurred during the night of August 14–15, 1945, shortly before the broadcast.
Army officers opposed to surrender tried to seize the Imperial Palace, prevent the recording from reaching the broadcasting station, and keep Japan fighting. The plotters searched for the recording of Hirohito’s Imperial Rescript, but they failed to find and destroy it. The Eastern District Army eventually helped restore order.
The broadcast went ahead at noon on August 15. The incident is sometimes called the Imperial Palace Incident in English, but “Kyūjō Incident” is the standard name used for the attempted coup. It did not overturn the Emperor’s decision, and Japan’s formal surrender was signed aboard USS Missouri on September 2.