When did the Battle of Lake Khasan occur?

The Battle of Lake Khasan (29 July – 11 August 1938), 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.

This incursion was founded in the belief of the Japanese side, that the Soviet Union misinterpreted the demarcation of the boundary based on the Treaty of Peking between Imperial Russia and Qing China (and subsequent supplementary agreements on demarcation) and that the demarcation markers were tampered with. Japanese forces occupied the disputed area but withdrew after heavy fighting and a diplomatic settlement.