Richard Sorge, a German communist, was a WWII Soviet spy who posed as a journalist in China and Japan. In October 1941, the Kempeitai (Japanese secret military police) arrested him on suspicion of working for the German Abwehr (German military intelligence). Under torture, he confessed that he was actually an agent of the Soviet GRU (Soviet foreign military intelligence). Although the Japanese repeatedly offered to trade Sorge for one of their own captured spies, the Soviets denied he was one of their agents and he was hanged in November 1944.
In 1964 the USSR acknowledged that Sorge had been a Soviet spy. Later it was learned that Stalin had failed to heed Sorge’s warning regarding the impending June 1941 German invasion of the USSR (Operation Barbarossa).