The Hundred Regiments Offensive was a significant military campaign initiated by the Eighth Route Army, part of the Chinese National Revolutionary Army, against the Japanese occupying forces in northern China. Launched in August 1940, the offensive aimed to disrupt Japanese military supply lines and improve morale among the Chinese populace. The campaign was the most extensive organized effort by the Communist Party's military wing at that time and was marked by strategic planning and execution over several weeks. The Eighth Route Army mobilized approximately 250,000 troops to conduct coordinated assaults across a vast area, targeting key infrastructure such as railroads, depots, and logistics hubs critical to the Japanese war effort.

The operations were notable for their scope, involving hundreds of regiments in dynamic and flexible guerilla tactics, which aimed at outmaneuvering the better-equipped Japanese forces. Despite initial successes, the offensive faced strong retaliatory measures from the Japanese military, which employed brutal counter-insurgency tactics against the local population. These tactics led to significant civilian casualties and suffering but ultimately highlighted the determination of the Chinese forces to resist foreign occupation. The campaign had mixed results strategically; while it inflicted damage on Japanese logistics, it also awakened severe counter-responses that showcased the dire conditions faced by those in occupied areas.

In the context of World War II, the Hundred Regiments Offensive represented a critical point in the Chinese resistance against Japan, revealing the capabilities of the Eighth Route Army and the Communist Party's growing influence. Moreover, the offensive played a role in the broader narrative of Chinese nationalism, emphasizing the struggle against invaders while pushing the narrative of unity among various factions in the fight for national sovereignty. This campaign highlighted the complexities of regional dynamics in China during the war and underscored the desperate need for internal solidarity against a common enemy.