On this day, 87 years ago, August 9, 1938 (July 14, 1938 in the lunar calendar), the Jinsui Border Region was formed. The cavalry troops of the 120th Division, which were galloping on the anti-Japanese front in northwest Shanxi, were formed in August 1938. In September last year, He Long and Guan Xiangying led the 120th Division of the Eighth Route Army to advance into northwest Shanxi to open an anti-Japanese base area. At the same time, they sent a large number of cadres to go deep into enemy-occupied areas to cooperate with the Ximeng Association of Shanxi Province and others to carry out the anti-Japanese armed struggle. At the end of the year, they opened an anti-Japanese base in northwest Shanxi with Guancen Mountain as the center and including more than ten counties. In February this year, the Japanese invaders took the opportunity of the 120th Division rushing to Tongpu Road to fight and mobilized tens of thousands of relatives to attack northwest Shanxi. The 120th Division was ordered to return and fought fiercely with the enemy for more than 20 days. It recovered seven counties and consolidated the anti-Japanese base areas in northwest Shanxi. In August, Li Jingquan, political commissar of the 358th Brigade of the 120th Division, led more than 2000 people to join forces with the anti-Japanese guerrillas led by Yang Zhilin to launch guerrilla warfare in Suizhong, Suixi, Suinan, Chahar and other places. At the end of the year, the Daqingshan Anti-Japanese Base Area was opened. The Northwest Shanxi Anti-Japanese Base Area and the Daqingshan Anti-Japanese Base Area were unified into the Jinsui Border Region.