During WWII, the Japanese aggressors committed atrocious crimes across the Chabei region in northern China. They spent years constructing extensive military fortifications and blockade trenches, and seizing grain, livestock, and other vital resources on a massive scale while exploiting and enslaving the local population. Civilians were arbitrarily detained and killed, and those suspected of supporting resistance forces were subjected to brutal torture. Countless people were displaced and plunged into dire suffering. Even more heinous, the Japanese army conducted large-scale bacteriological warfare in Zhangbei County and across the Chabei region. They forcibly conscripted locals for live human experimentation and deliberately spread epidemics throughout pastoral areas, inflicting untold misery upon the local population.
In August 1945, the Soviet Union and Mongolia declared war on Japan. Mechanized units of the Soviet and Mongolian forces crossed the border and advanced into the Chabei region to fight the Japanese aggressors. Guerrilla units of the Chinese Eighth Route Army operating behind enemy lines provided support. As a result, the main forces advanced with unstoppable momentum, and liberated multiple counties in the Chabei region. On August 15, Japan announced its unconditional surrender, and Zhangbei County was subsequently liberated.