The Tungchow Mutiny (Japanese: 通州事件 Hepburn: Tsushu jiken, Chinese: 通州事件; pinyin: Tōngzhōu Shìjiàn), sometimes referred to as the Tongzhou Incident, was the massacre of Japanese civilians and troops by East Hopei Army in Tongzhou, China on 29 July 1937 shortly after the Marco Polo Bridge Incident that marked the official beginning of the Second Sino-Japanese War. 223 of the 385 Japanese denizens were killed.
In early 1937, Tongzhou was capital of the East Hebei Autonomous Council, a Japanese puppet state controlling the strategic eastern district of Beijing. In July, a detachment of approximately 800 troops of the Chinese 29th Army, under the command of General Sung Che-yuan and loyal to the Kuomintang government, camped outside the walls of Tongzhou. Refusing to leave despite the strong protests of the Japanese garrison commander, the Japanese did not know that General Sung had reached an agreement with East Hopei leader Yin Je-keng, who hoped to use Sung's Kuomintang troops to rid himself of his Japanese overlords.
On 27 July, the Japanese commander demanded that the Kuomintang soldiers disarm. When they refused, fighting erupted the following day, and the outnumbered and outgunned Chinese troops were trapped between the Japanese and the city wall. However, the Kuomintang Chinese troops' unwillingness to surrender in what was essentially a suicide mission strongly affected the Japanese-trained 1st and 2nd Corps of the East Hopei Army who were attached to the Japanese army. When East Hopei Army units refused to press the attack, Japanese troops bombed their barracks on the evening of 28 July. On midnight of 28 July, some 5000 troops of the 1st and 2nd Corps of the East Hopei Army mutinied, turning against the Japanese garrison.
In addition to Japanese military personnel, some 260 civilians living in Tongzhou in accordance with the Boxer Protocol of 1901 were killed in the uprising (predominantly Japanese including the police force and also some ethnic Koreans). Only around 60 Japanese civilians survived and they provided both journalists and later historians with firsthand witness accounts. The Chinese set fire and destroyed much of the city.
Anti-Chinese sentiments were further intensified in Japan. The popular Japanese slogan in those days was "To punish China the outrageous" (Chinese: 暴戻支那膺懲; pinyin: Bōrei Shina Yōchō or its shorter version Chinese: 暴支膺懲; pinyin: Bōshi Yōchō). The Japanese military adventurists stationed in China used this incident to justify further military operations under the pretext of protecting Japanese lives and properties in and around Beijing.