In 1931, Japan staged the Mukden Incident and invaded Northeast China by force, then established a puppet state called Manchukuo. On 14 September 1936, the Japanese set up a special organization (滿鮮拓殖會社) and began to migrate Korean farmers to Northeast China in a planned systemic way. In 1945, when Japan surrendered at the end of World War II, there were more than 2.16 million Korean emigrants living in Northeast China. Among them, about 700,000 returned to Korea after the end of World War II. In 1947, the number of Korean emigrants decreased to 1.4 million, most of them living in the communist party controlled areas, only less than 100,000 living in the Kuomintang-controlled areas.