Kwantung Army

The Soviet Union had fought with Japan over the Manchurian border. An uneasy truce had existed since September 1939, when, in 1941, both nations realized that the coming war in Europe would mean that they would have to protect their interests elsewhere. Still, both nations had significant forces in Northern China in case the other attacked.

The Thirties were marked by confrontation and violence. The Western diplomats practicing Appeasement believed it would prevent another global war, but were woefully unaware of what they were dealing with. Most of the confrontation was between the ideologies of Nazism and Communism; they became mortal enemies in the thirties, which made their non-aggression pact and the dismemberment of Poland all the more shocking.

In 1938 and 1939, the Kwantung Army occupying Manchuria was severely defeated by the Red Army over a border dispute. Eager to score a victory, the Imperial Japanese Army was engaged in the border dispute near Khasan, where the borders of Manchuria, Korea and Siberia meet.