The Battle of Lake Khasan, also known as the Changkufeng Incident in China and Japan, was an attempted military incursion by Manchukuo, a Japanese puppet state, into the territory claimed and controlled by the Soviet Union. That incursion was founded in the Japanese belief that the Soviet Union had misinterpreted the demarcation of the boundary based on the Treaty of Peking between Imperial Russia and Qing China and the subsequent supplementary agreements on demarcation and tampered with the demarcation markers. Japanese forces occupied the disputed area but withdrew after heavy fighting and a diplomatic settlement.

The Russian Far East is a region in Northeast Asia. It is the easternmost part of Russia and the Asian continent; and is administered as a part of the Far Eastern Federal District, which is located between Lake Baikal in eastern Siberia and the Pacific Ocean. The area's largest city is Khabarovsk, followed by Vladivostok. The region shares land borders with the countries of Mongolia, China, and North Korea to its south, as well as maritime boundaries with Japan to its southeast, and with the United States along the Bering Strait to its northeast.