This article is about the 1931 invasion. For the 1894 invasion, see Japanese invasion of Manchuria (1894) . The Japanese invasion of Manchuria began on September 18, 1931, when the Kwantung Army of the Empire of Japan invaded Manchuria immediately following the Mukden Incident.The Japanese established a puppet state called Manchukuo, and their occupation lasted until the end of World War II.his article is about the 1931 invasion. For the 1894 invasion, see Japanese invasion of Manchuria (1894) . The Japanese invasion of Manchuria began on September 18, 1931, when the Kwantung Army of the Empire of Japan invaded Manchuria immediately following the Mukden Incident.