In the autumn of 1941, confronted with the Japanese army's "Three Alls Policy" and fortified blockades, local inhabitants originally excavated single-entrance concealment pits—termed "toad squats"—for shelter; however, these were readily obliterated due to their rudimentary design. Following the extensive Japanese "May 1st Sweep" in 1942, the Central Hebei Committee of the Chinese Communist Party and the military region advanced the development of tunnel building.[2] These developed into dual- and multi-entrance edifices, progressively establishing a vast subterranean network that linked residences and even villages, with an aggregate length surpassing 12,000 kilometers.[3]
The tunnels at Ranzhuang Village, Qingyuan County, exemplify a notable case. The network comprised four primary lines and 24 branches, extending around 16 kilometers in total. It included observation apertures, fire ports, traps, poison-resistant trapdoors, grain storage compartments, and a waterproofing system connected to wells.[4] Militia forces employed tunnels alongside landmines and guerrilla tactics, establishing a three-dimensional defense system through "three connections" (houses, tunnels, and bunkers) and "three interlocks" (open and concealed firepower, high and low firepower, and crossfire between streets and bunkers).[5] From 1942 to 1945, Ranzhuang's militia conducted 157 actions and provided support to main forces on 85 occasions. In a significant occurrence, they eliminated or injured 33 Japanese soldiers while sustaining only one minor injury among their defenders.[6]
Marshal Nie Rongzhen lauded tunnel warfare as “a significant innovation in overcoming adversaries on the plains.”[7] The Historic Site of Ranzhuang tunnel war [zh] was named a Major Historical and Cultural Site Protected at the National Level in 1961.[8]
