During the all-out War of Resistance Against Japanese Aggression, the guerrillas of the Eighth Route Army and the New Fourth Army actively opened up base areas and carried out guerrilla warfare behind enemy lines, resisting 58% of the Japanese invaders and 90% of all puppet troops, and the army also grew to 1.2 million regular troops, and another 2 million militia fought together. On the contrary, the Kuomintang army, after entering the stage of stalemate in the War of Resistance Against Japan, also transferred a large number of troops back to the enemy lines in North China, and stationed in the mountains and villages beyond the reach of the Japanese invaders, and before the Battle of Zhongtiao Mountain, the Kuomintang army in the occupied area had reached 1 million men.
Among these Kuomintang troops, they were mainly miscellaneous troops, and in the south, Li Zongren's troops stationed in the Dabie Mountain and Tongbai Mountain theaters were under the command of a hodgepodge of local troops such as the Gui Army and the Sichuan Army. In the north, the Jin Sui army of Yan Xishan, who retreated to the western Jin region; entrenched in the southern Hebei and northern Henan regions, Lu Zhonglin, Pang Bingxun, Sun Dianying and other old departments of the Northwest Army; Yu Xuezhong, who served as the commander of the Sulu Theater, was the former general of the Northeast Army.
However, there was also a place occupied by the Central Army of the Kuomintang lineage, that is, Zhongtiao Mountain, which was the horn of the three mountains of Taihang, Luliang and Taiyue. Here from the west of Jinnan Yongji and Shaanxi face, east to the north of Henan Jiyuan, Meng County and Taihang Mountain, north of the Yuncheng Basin, known as the granary of Shanxi reputation, south of the rolling Yellow River, the strategic position is very important.
In the early days of the War of Resistance Against Japanese Aggression, the Kuomintang and Communist armies actively cooperated and supported each other, and achieved certain results. In April 1938, more than 30,000 Japanese invaders launched a nine-way siege to the Taihang Mountains, and the Central Army and the Jinsui Army stationed in Shanxi fought jointly with the Eighth Route Army to smash the Japanese siege, annihilating more than 4,000 enemies and recovering 18 county seats. In September 1940, in order to prepare for the Battle of the Hundred Regiments of the Eighth Route Army, Yan Xishan's troops in Luliang Mountain, Wei Lihuang's troops in Zhongtiao Mountain, and Pang Bingxun's troops also made a certain number of sorties in the Taihang Mountain area.
However, after the Battle of the Hundred Regiments, the Japanese invaders recognized the threat of the Chinese army in the occupied area and began to shift their main forces to consolidate the occupied area. The Kuomintang troops in Shanxi, Hebei, Shandong, and the Dabie Mountains were all attacked by the Japanese and fierce battles ensued. Among them, the Battle of Zhongtiao Mountain is a representative battle. Due to its strategic importance, the Japanese launched 13 sieges on it. In May 1941, the Japanese invaders mobilized 6 divisions, 2 mixed brigades and 1 cavalry brigade to attack, and finally captured Zhongtiao Mountain, and defeated or captured the 260,000 Kuomintang troops stationed here.
At the same time that the Zhongtiao Mountain area was besieged, Yu Xuezhong was also fiercely attacked in the Lunan area and was forced to withdraw from Shandong; Lu Zhonglin was forced to resign and return to Chongqing, and Sun Dianying, Pang Bingxun and others led their troops to join the enemy; With the outbreak of the Pacific War, the Japanese invaders had to retreat with insufficient troops, and the Dabie Mountains and the surrounding areas were reoccupied by the Xingui system.
After August 1943, the Kuomintang only left the Dabie Mountains and the western Zhejiang base area in the south; In the north, especially in the area north of the Yellow River, only a dozen counties in the western part of the Jin Dynasty where the Jin Sui army was stationed were left, and they were barely preserved by the collusion between Yan Xishan and the Japanese invaders, and more than 500,000 troops had defected to the enemy among the millions of Kuomintang troops stationed behind enemy lines in the past.