The Jinan incident began as a 3 May 1928 dispute between Chiang Kai-shek's National Revolutionary Army (NRA) and Japanese soldiers and civilians in Jinan, the capital of Shandong province in China, which then escalated into an armed conflict between the NRA and the Imperial Japanese Army. Japanese soldiers had been deployed to Shandong province to protect Japanese commercial interests in the province, which were threatened by the advance of Chiang's Northern Expedition to reunite China under a Kuomintang government. When the NRA approached Jinan, the Beiyang government-aligned army of Sun Chuanfang withdrew from the area, allowing for the peaceful capture of the city by the NRA. NRA forces initially managed to coexist with Japanese troops stationed around the Japanese consulate and businesses, and Chiang Kai-shek arrived to negotiate their withdrawal on 2 May. This peace was broken the following morning, however, when a dispute between the Chinese and Japanese resulted in the deaths of 13–16 Japanese civilians. The resulting conflict resulted in thousands of casualties on the NRA side, which fled the area to continue northwards toward Beijing, and left the city under Japanese occupation until March 1929.