What was the name of the failed Japanese coup attempt that tried to stop Hirohito's surrender broadcast?

The failed Japanese coup attempt that tried to stop Hirohito's surrender broadcast was the Kyūjō incident.

The attempted coup took place during the night of August 14–15, 1945, shortly before the emperor's recorded address was scheduled to air. Hardline army officers and members of the Imperial Guard sought to prevent the surrender and place Hirohito under house arrest.

The plotters killed Lieutenant General Takeshi Mori and tried to create a false order authorizing their occupation of the Imperial Palace. They also searched for the phonograph recordings of Hirohito's speech so they could destroy them before broadcast.

The coup failed because senior military leaders did not support it and the rebels could not secure control of the palace or the national broadcasting system. The recordings were hidden and later delivered safely to NHK. The broadcast therefore went ahead at noon on August 15, helping make the surrender public throughout Japan.