On what date was Hirohito's surrender speech recorded before its broadcast to Japan?

Hirohito's surrender speech was recorded on August 14, 1945, before its broadcast the next day.

NHK sound technicians went to the Imperial Palace while Japanese officials debated the wording of the imperial rescript. Hirohito recorded the address late that night, and a second take was selected as the official recording after the first was considered unsatisfactory.

The recording was hidden during an attempted military coup by officers who wanted to prevent the surrender announcement. The rebels searched the palace but failed to locate the records, which were later carried safely to the broadcasting station.

At noon on August 15, NHK played the recording to the Japanese public. The distinction between the recording date and broadcast date matters: August 14 was when the Emperor's voice was captured, while August 15 was when the public heard it and Japan's surrender was announced.