Two wars are known by the title 'Sino-Japanese War'.
The first took place in 1894-95, sparked by the jostling of China and Japan for power in Korea. China was comprehensively defeated, and Japan established a protectorate over Korea and annexed Taiwan and Port Arthur, although was forced to give up Port Arthur under international pressure. Japan also occupied the naval base of Weihaiwei from 1895 to 1898, when it was leased from China by the United Kingdom. China's humiliating defeat gave impetus to the reform movement, and led to the Hundred Days reforms of 1898.
See also: Battle of the Yalu River
The second Sino-Japanese War broke out in 1937, after several years of Japanese provocations and encroachments on China, the most serious of these being the so-called Mukden Incident of 1931, which led to the Japanese occupation of Manchuria. On 7 July 1937 a skirmish between Japanese and Chinese troops at Lugouqiao ('Marco Polo Bridge'), near Beijing, led to a full scale Japanese invasion. By 1938 the main coastal cities, as well as Beijing, Nanjing and Wuhan, were in Japanese hands, and the Chinese government was resisting from a temporary capital at Chongqing. Although fighting was sometimes fierce, and took on a guerrilla character, little territorial change took place in the subsequent years until a major Japanese offensive in south-central China in 1944 led to the fall of Changsha and much of Hunan province. Japanese forces still held much of China at the conclusion of the war in August 1945.