Soviet–Japanese_border_conflicts--Emperor_Taishō

The Soviet–Japanese border conflicts, also known as the Soviet-Japanese Border War or the First Soviet-Japanese War or the Russo-Mongolian-Japanese Border Wars or the Soviet-Mongolian-Japanese Border Wars was a series of minor and major conflicts fought between the Soviet Union (led by Joseph Stalin), Mongolia (led by Khorloogiin Choibalsan) and Japan (led by Hirohito) in Northeast Asia from 1932 to 1939.
The Japanese expansion in Northeast China created a common border between Japanese occupied Manchuria and the Soviet Far East. This led to growing tensions with the Soviet Union, with both sides often violating the border and accusing each other of border violations. The Soviets and Japanese, including their respective client states of Mongolia and Manchukuo, fought in a series of escalating small border skirmishes and punitive expeditions from 1935 until Soviet-Mongolian victory over the Japanese in the Battles of Khalkhin Gol in 1939 which resolved the dispute and returned the borders to status quo ante bellum.
The Soviet–Japanese border conflicts heavily contributed to the signing of the Soviet–Japanese Neutrality Pact in 1941.