<P> In 1930, large - scale civil war broke out between warlords, who had fought in alliance with the Kuomintang during the Northern Expedition, and the central government under Chiang . In addition, the Chinese Communists (CPC, or Communist Party of China) revolted against the central government following a purge of its members by the KMT in 1927 . The Chinese government expended resources fighting these civil wars, following a policy of "first internal pacification, then external resistance" (Chinese: 攘 外 必 先 安 內). </P> <P> 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 (simplified Chinese: 九 一 八 事变; traditional Chinese: 九 一 八 事變; pinyin: Jiǔyībā Shìbiàn) in September 1931 . Japan charged that their rights in Manchuria, established by the Russo - Japanese War, had been systematically violated and that there were "more than 120 cases of infringement of rights and interests, interference with business, boycott of Japanese goods, unreasonable taxation, detention of individuals, confiscation of properties, eviction, demand for cessation of business, assault and battery, and the oppression of Korean residents ." </P> <P> After five months of fighting, Japan established the puppet state of Manchukuo in 1932, and installed last emperor of China, Puyi, as its puppet ruler . Militarily too weak to challenge Japan directly, China appealed to the League of Nations for help . The League's investigation led to the publication of the Lytton Report, condemning Japan for its incursion into Manchuria, causing Japan to withdraw from the League of Nations . No country was willing to take action against Japan beyond tepid censure . </P> <P> Incessant fighting followed the Mukden Incident . In 1932, Chinese and Japanese troops fought the January 28 Incident battle . This resulted in the demilitarisation of Shanghai, which forbade the Chinese from deploying troops in their own city . In Manchukuo there was an ongoing campaign to defeat the Anti-Japanese Volunteer Armies that arose from widespread outrage over the policy of non-resistance to Japan . </P>

When did china and japan go to war