On the evening of September 18, 1931, near the Shenyang suburb of Liutiaohu, a section of railway owned by Japan's South Manchuria Railway Company was rigged with dynamite and exploded. The widely accepted belief is that an officer with Japan's Kwantung Army laid the explosives in order to provide an excuse to initiate the second Sino-Japanese war, and the Japanese were quick to blame the Chinese army and attack the base camp of China's Northeast Corps. In the ensuing battle, the Chinese army outnumbered the Kwantung Army by several times, but most of the Chinese soldiers retreated on the orders of leader Chiang Kai-shek , who said that despite provocation, the Chinese army should try to avoid any conflict. A few hundred Chinese soldiers did fight back, with the battle leaving more than 300 of them dead or injured, against Japanese casualties of only 24. The incident, which led to Japan's invasion of Manchuria, is known as the September 18 incident on the mainland, the Mukden incident in the West - referring to Shenyang's former name - and the Manchurian incident in Japan. Within just five months of the incident, all the cities and towns in the three northeastern provinces Heilongjiang , Jilin and Liaoning had fallen. The campaign also increased the Japanese military's influence in Japan's government, leading to the eventual invasion of much of the rest of China and Southeast Asia and the attack on Pearl Harbour. September 18 is regarded by many Chinese as a day of national humiliation.