The Soviet–Japanese border conflicts, also known as the Soviet-Japanese Border War, the First Soviet-Japanese War, the Russo-Mongolian-Japanese Border Wars or the Soviet-Mongolian-Japanese Border Wars, were a series of minor and major conflicts fought between the Soviet Union, Mongolia and Japan in Northeast Asia from 1932 to 1939.

Manchukuo was a puppet state of the Empire of Japan in Northeast China that existed from 1932 until its dissolution in 1945. It was ostensibly founded as a republic, its territory consisting of the lands seized in the Japanese invasion of Manchuria; it was later declared to be a constitutional monarchy in 1934, though very little changed in the actual functioning of government. Manchukuo received limited diplomatic recognition, mostly from states aligned with the Axis powers, with its existence widely seen as illegitimate.