Introduction to guerrilla warfare and the anti-Japanese base areas behind enemy lines in North China: After the Eighth Route Army headquarters marched to the anti-Japanese front line in North China, it first achieved a great victory at Pingxingguan, breaking the myth of the undefeated Japanese army. The Yanmenguan ambush once cut off the enemy's ground supply line in front of Xinkou. The night attack on Yangmingbao Airport weakened the Japanese air power, restored the system of political commissars and political organs, and ensured the Party's leadership position in the army. From 1937 to 1938, the 115th Division of the Eighth Route Army established the Shanxi-Chahar-Hebei Anti-Japanese Base Area based on Mount Wutai, the 120th Division established the Shanxi-Northern Anti-Japanese Base Area centered on Guanjuan Mountain, and the 129th Division established the Shanxi-Hebei-Henan Anti-Japanese Base Area based on the Taihang Mountains.