The Battle of Lake Khasan (July 29, 1938 – August 11, 1938) and also known as the Changkufeng Incident (Chinese & Japanese: 張鼓峰事件, Chinese pinyin: Zhānggǔfēng Shìjiàn, Japanese pronunciation: Chōkohō Jiken) in China and Japan, was an attempted military incursion of Manchukuo (Japanese) into the territory claimed by the Soviet Union. This incursion was founded in the beliefs of the Japanese side that the Soviet Union misinterpreted the demarcation of the boundary based on the Treaty of Peking between Imperial Russia and Manchu Empire (and subsequent supplementary agreements on demarcation), and furthermore, that the demarcation markers were tampered with.