During the War of Resistance Against Japanese Aggression, there was an important military force in Shanxi and North China, that is, the Jin Sui Army, and the Jin Sui Army was also a modern army established earlier in China, its predecessor was the new army trained by the Qing government in Shanxi, by 1911, the decadent Qing government had long been unpopular, and the New Army in Shanxi, under the leadership of people of insight, also joined the ranks of overthrowing the Qing government, and the following year, Yan Xishan returned to Shanxi, and in the following time, gradually mastered the Jin Sui Army.
After Yuan Shikai's death, the whole country was also in chaos, and Yan Xishan also realized that if he wanted to survive the chaotic world, he must have a strong military ability, and then Yan Xishan also continued to expand his troops, and the strength of the Jin Sui Army increased greatly at this stage. After the outbreak of the War of Resistance Against Japan, Shanghai was soon lost, and Yan Xishan also joined the War of Resistance, and his Jin Sui Army was also organized into the Nationalist Army, and Yan Xishan was appointed commander of the Fifth Theater of Operations.
In October 1937, with the fall of North China, Shanxi was also exposed to the iron horse of the Japanese army, precarious, the main force of the Central Army at that time was drawn to the Songhu battlefield, and all were severely damaged, in early September, the Japanese army of more than 100,000 troops after taking Shanxi's Men Datong, tightly pressed the hinterland of Shanxi, the Jin Sui Army at that time had more than 100,000 people. In the face of the Japanese invasion, Yan Xishan also began to arrange combat deployment, arranged several defensive lines in the hinterland of Shanxi, and the Jin Sui Army was also all pulled to the battlefield, in order to block the Japanese attack, Wei Lihuang also served as a commander to reinforce.
At that time, the Japanese army participated in the war with more than 70,000 troops in 3 divisions, and was equipped with more than 350 heavy artillery, more than 200 tanks, and more than 300 aircraft. In order to be able to hold the front-line position, the Chinese army went forward and followed, and did not hesitate to block the armored vehicles of the Japanese army with their flesh and blood. All 8 armies of the Nationalist army were thrown into the battlefield, and when the war was at its most intense, the entire regiment of the Chinese army was wiped out. For this battle, Yan Xishan also fought with all his strength, transferring all the families of the Jin Sui army to the front line, and he threw all his heavy artillery into the Battle of Xinkou. Helplessly, the Japanese army had the advantage of air firepower, and Yan Xishan's artillery often did not fire a few shells, and they would be destroyed by the bombing of Japanese aircraft.
At the most tragic time of the battle, the strength of a regiment of the Jin Sui Army was pulled to the front line, and after an hour, it was almost exhausted. In this battle, Lieutenant General Hao Mengling, commander of the Nationalist 9th Army, Lieutenant General Liu Jiaqi of the 54th Division, Major General Jiang Yuzhen of the 196th Brigade, Major General Zheng Tingzhen, commander of the Independent 5th Brigade, and his acting brigade commander were killed one after another, and division commander Li Xianzhou, brigade commander Yu Zhenhe and Dong Qiwu were seriously wounded, and no less than dozens of battalion commanders were killed in the battle, which shows the tragic degree of the battle situation at that time.
After more than 20 days of bitter fighting, the Nationalist army was finally unable to block the Japanese offensive, and the Japanese army also suffered more than 20,000 casualties in the Battle of Xinkou, after the fall of Xinkou, Taiyuan was also in no danger, and Shanxi was quickly occupied by the Japanese army.