Richard Sorge
http://www.spartacus.schoolnet.co.uk/GERsorge.htm
After studying he also secretly joined the German Communist Party (KPD) and while working in Japan in 1933 began working as a spy for the Soviet Union.He also posed as a loyal Nazi and worked as an espionage agent for the German embassy in Japan. This enabled him to find out information about Germany's intentions towards the Soviet Union.
Sorge was able to give Joseph Stalin advance warning about the Anti-Comintern Pact (1936), the German-Japanese Pact (1940) and Japan's attack on Pearl Harbour. His greatest achievement was to inform the Soviet Union of Operation Barbarossa as early as December, 1940.
As Leonard Trepper, the head of Red Orchestra, later pointed out: "The generalissimo preferred to trust his political instinct rather than the secret reports piled up on his desk. Convinced that he had signed an eternal pact of friendship with Germany, he sucked on the pipe of peace."
At the end of August, 1941, Sorge was able to tell Joseph Stalin that Japan would not attack the Soviet Union that year. Two months later Sorge was arrested in Tokyo and held in prison for three years. The Soviet Union refused to exchange Sorge for Japanese prisoners they held and he was hung on 7th November, 1944.
After the war Leopold Trepper met General Tominaga, Chief of Staff of the Japanese Army in Manchuria. During the meeting he asked Tominaga about Richard Sorge.
"Do you know anything about Richard Sorge? I asked him.
"Naturally. When the Sorge affair broke out I was Vice-Minister of Defence."
"In that case, why was Sorge sentenced to death at the end of 1941, and not executed until November 7, 1944.? Why didn't you propose that he be exchanged? Japan and the USSR were not at war" (The USSR officially declared war on Japan on August 8, 1945)
He cut me off energetically. "Three times we proposed to the Soviet Embassy in Tokyo that Sorge be exchanged for a Japanese prisoner. Three times we got the same answer: "The man called Richard Sorge is unknown to us."
20 years later he was made hero of USSR, and also a stamp of him was made!!!
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http://www.angelfire.com/dc/1spy/Sorge.html
The last coded message by Sorge was deciphered in Moscow ( Ocotber 1941 ) and read:
"Japanese carrier force attacking United States Navy at Pearl Harbor, probably dawn, 6th November."
Stalin did not take the trouble to inform the U.S., his ally.
http://www.geocities.com/Pentagon/6315/pearl.html
Oct.1941 - Soviet top spy Richard Sorge, the greatest spy in history, informed Kremlin that Pearl Harbor would be attacked within 60 days. Moscow informed him that this was passed to the US. Interestingly, all references to Pearl Harbor in the War Department's copy of Sorge's 32,000 word confession to the Japanese were deleted. NY Daily News, 17 May 1951.
http://www.rooseveltmyth.com/FinalSecret/chap7.html
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Sorge seems to have saved the Russians with his information as they could transfer troops to the Moscow front!