Most significantly, Sorge gave military planners in Moscow two pivotal bits of information in 1941 - that Nazi Germany was massing divisions on its eastern front in preparation for an offensive against the Soviet Union that would scrap a non-aggression pact signed by Ribbentrop and his Soviet counterpart in 1939, and that Japan, despite its alliance with Nazi Germany, would focus its troops on the war effort in China as well as making inroads further afield into Southeast Asia and the Pacific.
Any decision on opening a new front against the Soviets would be contingent on how swiftly the Nazi offensive succeeded.
Eventually, Sorge became certain that Japan had its hands full, and was also planning an assault on the US.
"In the careful judgment of all of us here ... the possibility of [Japan] launching an attack [on the USSR], which existed until recently, has disappeared," Sorge reported to Moscow in September 1941.
Stalin was convinced, and the Soviets moved a huge part of their Far Eastern reserves to the west.
"In the next two months, 15 infantry divisions, 3 cavalry divisions, 1700 tanks, and 1500 aircraft moved from the Soviet Far East to the European front," wrote historian Stuart Goldman.
"It was these powerful reinforcements that turned the tide in the Battle of Moscow in the first week of December 1941, at the same time Japan attacked Pearl Harbour."
The desperate Soviet resistance against the Nazi war machine was perhaps the single most important factor in the Allied victory against Hitler in World War II. For his vital piece of intelligence, Sorge forever earned his place in the history of espionage.
But he was already a larger than life figure. Born in 1895 in what's now Azerbaijan to a Russian mother and a German engineer father, Sorge grew up in Germany and came of age in the trenches of World War I, where he was injured.
While recuperating, he developed Marxist sympathies and spent the next decade shuttling between Germany and the Soviet Union, leaving a string of wives, mistresses and lovers in his wake.
Sorge eventually joined the Red Army's military intelligence unit and then went about building up his Nazi bona fides in Berlin.
A notoriously heavy drinker, he abstained from alcohol while in Nazi beer halls to ensure that he wouldn't give himself away with a slip of the tongue.
"That was the bravest thing I ever did. Never will I be able to drink enough to make up for this time," he supposedly told Hede Massing, an Austrian actress turned Soviet agent who later defected to America.
By 1933, Sorge was at his post in Japan and set about insinuating himself into German and Japanese diplomatic circles. In October 1941, the Japanese uncovered Sorge's spy ring and arrested him and his co-conspirators. He was hanged three years later.
Until his arrest, Sorge had maintained a concerted party lifestyle, and had many admirers.
Unlike other Soviet spooks later outed after World War II, Sorge has maintained a largely heroic quality.
Ian Fleming, the author of the spy novels that would give the world James Bond, hailed Sorge as "the man whom I regard as the most formidable spy in history."
- Washington Post-Bloomberg
