The master recording of Emperor Hirohito's speech announcing Japan's World War II surrender has been brought back to life in digital form ahead of the 70th anniversary of the end of the war.

The Imperial Household Agency on Saturday released the original audio from the vinyl master records of Hirohito's radio broadcast on August 15, 1945.

The surrender speech by the emperor, known as the "jewel voice broadcast", had been available only as a low quality copy made by the US occupying forces in 1946.

The four-and-a-half minute speech, which was digitally remastered by the agency, has been made available to the public on the agency's website: www.kunaicho.go.jp
Background noise can still be heard in the new version but an agency official was quoted by the Yomiuri Shimbun as saying: "The voice pitch and intonation reflected the emperor's natural atmosphere and was close to his real voice."

In the speech the emperor announced the nation's acceptance of the Potsdam Declaration, which demanded Japan's unconditional surrender, pledging "to pave the way for a grand peace for all the generations to come by enduring the unendurable and suffering what is unsufferable".

The speeched was recorded on August 14 at the Imperial Palace and the emperor's announcement was broadcast at noon the following day. The speech marked the first time most Japanese heard the emperor's voice.
The five vinyl master records, which have been kept as part of the imperial family's collection, are among historical documents and materials made available to the public this year to mark the war-end anniversary.

The agency also released photos and films of a bomb shelter at the palace, which has not been used since the end of the war.

The shelter was the venue of an imperial conference on August 14, 1945, when the emperor officially decided to surrender days after the US dropped atomic bombs on Hiroshima and Nagasaki.

The recently-taken pictures showed decayed wooden walls and rusted steel doors of the shelter -- hardly recognised as former key facilities for Emperor Hirohito, who was worshipped as a "living god" before the war.

"We judged it is of great significance to make the major symbolic items related to the end of the war widely known to the public at the timing of the 70th anniversary," the agency said, according to Kyodo News.