The Battle of Pingxingguan, commonly called the "Great Victory of Pingxingguan" in Mainland China, was an engagement fought between the 8th Route Army of the Chinese Communist Party and the Imperial Japanese Army on September 25, 1937.
It resulted in a minor, morale-boosting victory in which 8th Route Army was able to capture a cache of weapons and annihilate a Japanese brigade.
After the capture of Beiping (present Beijing) at the end of July, Japanese forces advanced along the Beiping-Suiyuan railway line 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-Kuomingtang 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 Huaili, 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 September 13, falling back to a line from Yanmenguan 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.
The pass of Pingxingguan was a narrow defile worn through the loess, with no exit for several kilometres except the road itself. Having pushed their way through many easily defensible position, the Japanese were careless and contempuous, and began their march through the pass without scouting or securing the heights on either side. At about 9000 men, Lin's division was of respectable strength, and had enough rifle and machine guns to make an impression.
At dawn on September 25 Lin attacked the head of the Japanese column, at noon the centre and rear. The battle consisted chiefly of Chinese troops shooting and throwing hand grenades into the packed mass of Japanese soldiers trapped in the defile fifteen feet below their attackers. When it was over there were about 1000 Japanese killed and 1000 Chinese casualties (according to the latest Chinese history book).