The Battle of Pingxingguan (), commonly called the Great Victory of Pingxingguan in Mainland China, was an engagement fought on 25 September 1937, at the beginning of the Second Sino-Japanese War, between the Eighth Route Army of the Chinese Communist Party and the Imperial Japanese Army. The battle resulted in the loss of 400 to 600 soldiers on both sides, but the Chinese captured 100 trucks full of supplies. The victory gave the Chinese Communists a tremendous boost since it was the only division-size battle that they fought during the entire war. Background After the capture of Beiping (present Beijing) at the end of July 1937, Japanese forces advanced along the Beijing–Baotou railway to Inner Mongolia. Having anticipated the move, Chiang Kai-shek had appointed the Shanxi warlord Yan Xishan as Pacification Director of Taiyuan. Theoretically Yan had authority over all the Chinese military forces in his theatre of operations, including Lin Biao's 115th Division of the Communist 8th Route Army, Liu Ruming's ex-Kuomintang troops and various Central Army contingents responsible to Chiang Kai-shek. In reality these forces operated independently from Yan's provincial army. Japanese forces, mainly the 5th Division and 11th Independent Mixed Brigade, moved out from Beiping and advanced on Huailai County in Chahar. A Japanese column advanced quickly into Shanxi, making use of the railway which the Chinese did not attempt to destroy. The Chinese abandoned Datong on 13 September, falling back to a line from Yanmen Pass on the Great Wall east to the mountain pass of Pingxingguan. Yan Xishan's troops became more demoralised as the Japanese exerted their air supremacy. The main body of the Japanese 5th Division, under the command of Itagaki Seishiro, advanced from Huaili to invade northeastern Shanxi. Although it had a motorised transport column, its rate of advance was limited by the poor roads. By the time they reached the Shanxi border, Lin Biao's 115th Division, after a forced march from Shaanxi, was in place at Pingxingguan on 24 September to ambush the Japanese army. Battle The pass of Pingxingguan was a narrow defile worn through the loess, with no exit for several kilometres except the road itself. Lin's division were able to ambush two columns of mainly transportation and supply units and virtually annihilate the trapped Japanese forces. On 25 September, the 21st brigade of the Japanese 5th Division stationed at Lingqiu received a request from the 21st Regiment that they