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NHK had been created in 1926 and was modeled after the BBC. Before WWII it was a perfectly mudane news radio service. In November 1941, the Japanese Army nationalized it. The newly born propaganda machine was was shut down 4 yeras later immediately following the Emperor's concession speech in 1945.
The Japanese Imperial Army's 8th Section G-2 Psychological Warfare coordinated the national
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Iva was one of these DJs. The head of G-2, Major Tsuneishi decided to have his POWs broadcast a news program of such items to demoralize front-line U.S. troops. The show would be called the Zero Hour. The shows following came from the fact that it contained both popular jazz and content that had been censored from Allied news broadcasts. By November of that year they also added female announcers to further entire allied listening. You can hear recordings of her here: http://www.earthstation1.com/Tokyo_Rose.html
After the war, she was convicted of treason and imprisoned, released early for good behavior. She maintained her innocence, asserting that she had not said the words used to convict her, and that she had remained a loyal American. Though forced to broadcast to the troops, she claimed that she, with the help of American POWs assigned to the radio broadcasts, made herself and her words purposefully ridiculous. She had refused to give up her American citizenship, despite pressure and even punishment from the Japanese who forced her into the broadcasting role.
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*In a related but truly weird note, according to documents found in a 1974 Freedom of Information Act request the US Army Intelligence’s beleived (at least in 1944) that Amelia Earhart was Tokyo Rose.