After the Japanese invasion of Manchuria began on September 19, 1931, the whole Manchuria was seized by Japan following the Mukden Incident. Mudanjiang experienced a substantial growth in the 1930s under the Japanese occupation. Mudanjiang also became a military and administrative center going by the name Botankou, particularly after the railway from Tumen to Jiamusi was constructed in 1933. By that time several light industries including light engineering, lumbering, and food processing was established in the town. On December 1, 1937, Botankou City was established by the Manchukuo government, administering five counties. On October 15, 1938, Japanese Government set up a consulate in Botankou and promoted Botankou as a municipality directly under the Manchukuo Government. As Manchukuo collapsed, Mudanjiang was captured by the Soviet Army on August 16, 1945.