Jewel Voice Broadcast

The (or less literally, "broadcast in the emperor's own voice") was a radio broadcast of surrender given by Japanese Emperor on August 15, 1945. It announced to the Japanese people that the Japanese Government had accepted the Potsdam Declaration demanding the unconditional surrender of the Japanese military at the end of World War II. Following the Hiroshima bombing on August 6th, the Soviet declaration of war and the Nagasaki bombing on August 9th, the Emperor's speech was broadcast at noon Japan Standard Time on August 15, 1945, and did reference the atomic bombs as a reason for the surrender. 
The speech was probably the first time that an Emperor of Japan had spoken (albeit via a phonograph record) to the common people. It was delivered in formal Classical Japanese, which contained many Chinese-origin characters and pronunciation that were unfamiliar to ordinary Japanese. The speech made no direct reference to a surrender of Japan, instead stating that the government had been instructed to communicate to the United States, the United Kingdom, China and the USSR to accept "their joint declaration" (though the USSR was not, in fact, part of the declaration). This created confusion in the minds of many listeners who were not familiar with the declaration and were not sure whether Japan had surrendered. Both the poor audio quality of the radio broadcast and the formal courtly language in which the speech was composed worsened the confusion. A digitally-remastered version of the broadcast was released on June 30, 2015.
Recording.
The speech was not broadcast directly, but replayed from a phonograph recording. On August 14, 1945, the NHK dispatched sound technicians to the Imperial Palace to record the broadcast. Microphones were set up in an office bunker under the Imperial Household Ministry, and Emperor Hirohito proceeded in between 11:25pm and 11:30pm. During the first recording he spoke too softly, and upon the advice of the technicians, offered to rerecord it. On the second attempt, his voice was considered too high pitched, with occasional characters being skipped. Nevertheless, the second version was deemed the official one, with the first serving as a backup.
Broadcast.
Many elements of the Imperial Japanese Army were extremely opposed to the idea that the emperor was going to end the war, as they believed that it was dishonourable. Consequently, as many as 1,000 officers and soldiers raided the Imperial palace on the evening of August 14 to destroy the recording. The rebels were confused by the layout of the Imperial palace and were unable to find the recordings, which had been hidden in a pile of documents. The two phonographs were labelled 'ORIGINAL' and 'COPY' and successfully smuggled out of the palace, the original in a lacquer box and the copy in a lunch bag. Major Kenji Hatanaka attempted to halt the broadcast at the NHK station but was ordered to desist by the Eastern District Army.
On August 15, 1945, at precisely noon, the national anthem, , was played, followed by the Emperor's speech.
To ease the anticipated confusion, after the conclusion of the speech, a radio announcer clarified that the Emperor's message had meant that Japan was surrendering. According to French journalist Robert Guillain, who then lived in Tokyo, upon the announcement's conclusion, most Japanese retreated into their homes or places of business for several hours to quietly absorb and contemplate the significance of the announcement.
The recording disappeared in the post-surrender chaos, but a radio technician had secretly made a copy, which was given to Occupation authorities and is the source of all recordings available today. The original record was later recovered but is generally believed to have never again been played.
Content.
Though the word "surrender" was not explicitly stated, the emperor instructed his government to communicate to the Allies that the "empire accepts the provisions of their joint declaration", which amounted to an acceptance of the Potsdam Declaration. He justified Japan's decision to go to war as an act of "self-preservation and the stabilization of East Asia" and referenced the setbacks and defeats of recent years, saying "the war situation has developed not necessarily to Japan's advantage". He mentioned the atomic bombings of Hiroshima and Nagasaki that had occurred days earlier, calling the atomic bomb a "new and most cruel bomb", but omitted the Soviet invasion of Manchuria as the final impetus for surrender. The emperor ended with a call on the Japanese people "to be devoted to construction for the future".
The broadcast was translated into English and broadcast internationally by radio presenter at the same time. In the U.S., the Federal Communications Commission (FCC) recorded the broadcast, and its entire text appeared in "The New York Times".