answers: 1937
context: government in Nanjing decided to focus their efforts on suppressing the Chinese Communists through the Encirclement Campaigns, following the policy of "first internal pacification, then external resistance" (). The internecine warfare in China provided excellent opportunities for Japan, which saw Manchuria as a limitless supply of raw materials, a market for its manufactured goods (now excluded from the influence of many Western countries in Depression-era tariffs), and as a protective buffer state against the Soviet Union in Siberia. Japan invaded Manchuria outright after the Mukden Incident in September 1931. Japan charged that their rights in Manchuria, established by the Russo-Japanese </s> Settlement, where 30,000 Japanese civilians lived with 30,000 troops on August 12, 1937. On August 13, 1937, Kuomintang soldiers and warplanes attacked Japanese Marine positions in Shanghai, leading to the Battle of Shanghai. On August 14, Kuomintang planes accidentally bombed the Shanghai International Settlement, which led to more than 3,000 civilian deaths. In the three days from August 14 through 16, 1937, the Imperial Japanese Navy (IJN) sent many sorties of the then-advanced long-ranged G3M medium-heavy land-based bombers and assorted carrier-based aircraft with the expectation of destroying the Chinese Air Force. However, the Imperial Japanese Navy encountered unexpected resistance from </s> Operation Ichi-Go, their largest offensive of World War II, to attack the American airbases in China and link up the railway between Manchuria and Vietnam. This brought major cities in Hunan, Henan and Guangxi under Japanese occupation. The failure of Chinese forces to defend these areas encouraged Stilwell to attempt to gain overall command of the Chinese army, and his subsequent showdown with Chiang led to his replacement by Major General Albert Coady Wedemeyer. By the end of 1944 Chinese troops under the command of Sun Li-jen attacking from India, and those under Wei Lihuang attacking from Yunnan, joined forces
question: when did world war 2 start in china