In 1931, the Japanese Kwangtung Army attacked Chinese troops in Manchuria in an event commonly known as the Manchurian Incident. Essentially, this was an attempt by the Japanese Empire to gain control over the whole province, in order to eventually encompass all of East Asia. This proved to be one of the causes of World War II. Japan modernized between 1868 and World War One. It emerged as a modern industrial economy with giant companies - zaibatsus - that assumed great importance as trading enterprises. Japans expansion was marked by wars of expansion - defeats China over Korea in 1894-5 and Russia over Manchuria in 1904-5. The latter war sees the Japanese navy sink Russias at the Battle of Tsushima in 1905. The Japanese navy had led Japan into the ranks of modern industrialized powers. In World War One Japan acquired German islands north of the Equator. In the Depression Years, Japan moves to acquire an Empire - The East Asia Co-Prosperity Sphere. This was due largely to the break-up of the world into trade blocs with Japan frozen out of many markets. The 1929 Depression hit Japan hard. The civilian government had no solutions to the problems presented by the worldwide depression and the civilian government looked weak. The unemployed of Japan looked to the strength of the army to assist their plight rather than to weak politicians. The voice of senior army generals were heard and they argued campaign to win new colonies abroad so that the industries there could be exploited for Japan. Japan invaded Manchuria in 1931, which caused many blames by the League of Nations. By 1931, Japan had invested vast sums of money into the economy of Manchuria, which was effectively controlled by the South Manchuria Railway Company. In 1937 Japan invaded China and, after the collapse of France, moved to acquire bases in French Indo-China- this led by degrees to the war in the Pacific, especially after the US oil embargo in July 1941. Japan struck at US and UK bases in Dec.1941. The most obvious target was a full-scale invasion of Manchuria. The Manchurian Incident marked a significant change in Japans foreign policy, especially towards its colony of Korea. The Japanese wanted to compete in a geopolitical struggle for domination with the United States, the Soviet Union, and many of European countries that had ambitions to hold their colonies in Asia. The invasion of Manchuria and the war mobilization efforts attempted to create a strong empire, which could eventual compete with these world powers. The Japanese government set up a puppet state of Manchukuo after they took over Manchuria. Manchuria was also taken in an effort to curb the advance of Chinese nationalist forces, which were threatening Japanese interests on the Asian continent. Manchuria was also used for their vast Natural Resources and raw materials, which would help further the economic goals of Japan. The war effort in Korea and China included the mobilization of labor, in which the workers could be moved to various parts of the Japanese Empire, all to insure production for the war effort. Koreans worked in factories and mines in Manchuria, northern Korea and Japan. About 4,000,000 Koreans and Chinese were displaced from their homes and shipped to these factories so that they would be productive in Japans war efforts. The war mobilization scattered Koreans and Chinese, as manpower, all over East Asia, in an effort to maximize production for the mother country.