Overview

The art of siegecraft is incredibly sophisticated and complex, often involving meticulous planning on logistics, morale, tactics, intelligence, diplomancy, and so on. However, when it comes to taking direct action against a fortification, the options are surprisingly few. The vast majority of siege tactics all over the pre-modern world generally revolved around circumvallation, artillery bombardment, tunnelling and sapping, escalade, siege tower, battering ram as well as thermal attack, and China was no exception. As such, Chinese countermeasures to most siege tactics were more or less identical to methods developed elsewhere.

What set them apart from other cultures was that larger Chinese walls allowed the defenders to set up heavier and more complex machinery on the battlement, or even move their own siege engines anywhere on the wall to counter enemy siege engines, without the need of artillery position prebuilt into the wall.

1) Circumvallation countermeasure

Circumvallation, known as Ju Yin (距堙 or 距闉) in Chinese, was a tactic used by pretty much all pre-modern armies to lay siege to a fortified position by constructing a line of siegeworks to partially or completely surround the target fortification. Circumvallation allowed the attacking party to enforce blockade more effectively, reconnoitre enemy defensive layout from a high position, and even pour suppressive fire against defending troops on the wall. It could also serve as a base for launching assaults against enemy fortification, or for constructing further earthworks such as siege ramps or tunnels. Chinese circumvallation tactics range from simple Jin Lang (井闌) towers built atop artificial mounds and ditches, to more elaborate palisades and fortified arrow towers, to full-blown encirclement with networked siege castles.

1.1) Sortie

Due to the limitations of pre-gunpowder siege weapons (stone throwers have limited range and generally cannot demolish fortified structures faster than they can be repaired/rebuilt), it was extremely difficult to stop a circumvallation attempt once the construction process started. As such, the best countermeasure to enemy circumvallation was to sortie out to destroy enemy fortifications, siege engines and earthworks before they could be completed, preferably with armed escorts and covering fire from friendly troops on the wall. While undoubtedly effective, this tactic was not without downsides, as it was extremely risky and wasn't always viable against numerically superior enemy.

1.2) Counter-tunnel

Just as tunnelling could be used to bring down a fortification, so too it was an effective countermeasure against circumvallation. Countermining tactics will be discussed in section 3.2) Countermining.

1.3) Tower hoarding

Multi-storey hoarding built on the wall could offset the height advantage of enemy circumvallation.