Chinese fortification: an overview of parts and terminology — Part 1: The wall

UPDATED JUNE 10, 2024

A recent discussion in the comment section of my previous blog post has sparked my interest in learning more about Chinese fortification (that and marathoning Castles! YouTube video series). To my surprise, despite having some of the most well-known fortifications in the world such as the Great Wall of China, Chinese fortification is very little studied and understood, and researching for information proved more difficult than my anticipation due to various reasons. Chief among the reasons is the large-scale movement to demolish old city walls in the 1920 to 1950s as China tried to modernise (in fact there are only three places with authentic and relatively intact major city walls: Pingyao, Jingzhou, and some parts of Xi'an), meaning that many historical sites, along with the knowledge about their designs, were wiped out. Modern historians also tend to overlook military history, so many design features on the surviving walls are either misunderstood, misnamed, or forgotten altogether. It doesn't help that many available information are diluted for tourist consumption, and tour guides certainly don't make good historians!

Overview

For most of its long history, China was ruled by a centralised bureaucratic government and had a highly nationalised military establishment. As China's centralised government could mobilise more resources and form cohesive defence strategy on a grand scale, Chinese fortification strategy focused on building up an interconnected network of fortified settlements, military fortresses, outposts, chokepoints, postal/relay stations, watchtowers, and most importantly, the Great Wall. As such, Chinese people generally did not build fortified private residence in the manner of European medieval castle (barring a few notable exceptions, such as the late Ming-high Qing period House of the Huangcheng Chancellor), and the state would've actively discourage such practise.

Due to the emphasis on protecting the settlement, fortified wall became the centrepiece of Chinese fortification. A wall was the last line of defence against the attackers, and very often the first line as well. Thus it is no surprise that Chinese people became the world's greatest wall builders. Virtually all cities and towns in China, as well as a significant numbers of villages, were walled. In contrast, Chinese fortification layout tend to be very simple. The vast majority of Chinese walled cities were nothing more than settlements surrounded by a wall and a moat, with the main city gate almost always placed facing the south.

Parts of a Chinese fortification

Basic layout of a Chinese city gate, from 'Wu Bei Zhi (《武備志》)'.

1) The wall

The first part of this series will provide an overview of various types of Chinese fortified walls, as well as facilities, superstructures, and hoardings that can be found on the wall. Note that italicised names are likely modern terminology. The original names were either lost, or I am unable to find them.

Cheng (城, lit. 'Fortified wall')

Aerial view of the city wall of Xi'an.

The wall was the single most important component of Chinese fortification. Chinese people built their walls and foundations out of rammed earth, sometimes mixed with sand, gravels, rubbles and ceramic debris, as well as reinforced with wooden piles, granite blocks or brick pavement. From Tang and Song Dynasty onwards, most walls were also lined with the unique Chinese blue bricks (which give Chinese walls their bluish-grey hue), and bound with equally unique limestone-glutinous rice paste mortar mixture. The resulting walls were extremely tall and thick, and nearly impervious to all but the heaviest of siege cannons.

A miniature model showing the cross-section of a Chinese wall.

Zi Cheng (子城, lit. 'Child wall')

Zi Cheng refers to the wall of the inner city, and by extension the inner city itself.

Luo Cheng (羅城, lit. 'Rounding wall')

Luo Cheng refers to the wall of the outer city, and by extension the outer city itself. A particularly large Chinese walled city can have more than one Luo Cheng.

Yi Cheng (翼城, lit. 'Wing wall')

Yi Cheng refers to the extra wall section extending from the Luo Cheng that encloses the suburb of a city. As a city grew in size, sometimes the wall of Luo Cheng separating the outer city and the suburb would be demolished, and Yi Cheng became the new Luo Cheng.

Yi Cheng can also refer to twin satellite fortresses that flank a main fortress from two opposite directions.

Ya Cheng (牙城, lit. 'Fang fort')

Ya Cheng refers to a citadel built inside the inner city that houses the private residence of a military commander, in particular a Tang Dynasty Jie Du Shi (節度使), as well as the facilities for his associated guards, officers and personal army. After the downfall of Tang Dynasty and the abolishment of Jie Du Shi institution, the citadel came to be known as Ya Cheng (衙城, lit. 'Government office city') and was used to house various government buildings instead.

Man Zhou Cheng (滿洲城, lit. 'Manchu city')

Old photo of the Manchu garrison city of Qingzhou.

Man Zhou Cheng, also known as Man Cheng (滿城, lit. 'Manchu city'), Qi Cheng (旗城, lit. 'Banner city') and Zhu Fang Cheng (駐防城, lit. 'Garrison city'), refers to a walled "city within a city" built during Qing period to serve as military garrison and to segregate Manchu people/Manchu bannermen from Han Chinese population.

Most of these cities were destroyed during Taiping Rebellion and Xinhai Revolution.

Han Cheng (捍城, lit. 'Guarding wall') and Hu Cheng (護城, lit. 'Protection wall')

Han Cheng at the base of one of the gates of Taizhou city wall. It should be noted that the wall is partially sunken under modern pavement, so it appears to be slightly shorter than it really is.

Han Cheng and Hu Cheng are special wall features unique to the city wall of Taizhou, sometimes known as "Southern Great Wall of China". Han Cheng refers to a small auxiliary wall, about two metres in height, built at the base of the outer side of the main wall, while Hu Cheng refers to its slightly taller counterpart built at the inner side. Both are designed to reinforce the main wall against frequent river flood that plagued the region.

Er Cheng (耳城, lit. 'Ear wall')

Modern line illustration of the layout of Shenbicheng Fortress, with its doubled Er Cheng highlighted red.

Er Cheng is a fortified wall that extends out, and completely encloses, a section of the main wall. Usually built to protect a vulnerable gatehouse, it serves to deny a critical position to enemy siege engines which may otherwise outrange the defenders on the main wall.

Unlike the similar Yue Cheng (月城), Er Cheng does not come with a gate of its own.

Yi Zi Cheng (一字城, lit. ''One' ideograph wall')

Scale model of the famous Diaoyu Fortress. Wall section marked with a white arrowhead is the southern Yi Zi Cheng of the fortress.

Yi Zi Cheng refers to a wall section that extrudes away from the main wall to a nearby river, or sometimes even into it. A special fortification feature almost unique to Southern Song period during the Mongol invasion of China, Yi Zi Cheng serves to safeguard the city/fortress's access to nearby water (allowing the city/fortress to be supplied through the river). It also prevents the enemy from surrounding the city/fortress from all sides, or simply circumvent the city/fortress and attack somewhere else.

1.1) Wall facilities

Deng Cheng Ma Dao (登城馬道, lit. 'Wall-scaling horse route')

Deng Cheng Ma Dao of the city wall of Nanjing.

Deng Cheng Ma Dao, or simply Ma Dao (馬道, lit. 'Horse route'), refers to the facility that allows the defending troops to access the battlement at the top of the wall, typically incorporating both stairway and ramp. It is also known as Shang Cheng Deng Dao (上城蹬道, lit. 'Wall-accessing stairway').

Nu Qiang (女牆, lit. 'Woman's wall')

Battlement on top of Shenyang city wall.

Also known as Die (堞) and less commonly Pi Ni (睥睨, lit. 'Peek'), Nu Qiang refers to the parapet built at the edge of a wall. It can refer to both crenellated battlement and uncrenellated parapet.

Yu Qiang (宇牆)

Yu Qiang on the city wall of Xi'an during winter.

Yu Qiang is a subtype of Nu Qiang that is built at the inner edge of a wall for safety.

Nu Tou (女頭, lit. 'Woman's head')

A merlon of the city wall of Kaifeng.

Nu Tou is the Chinese term for merlon. It is also known as Duo (垛) and Die (堞).

Step tapered merlons on the Song period city wall of Zhaoqing.

Early Chinese merlons were generally step tapered. However, increased intensity of siege warfare during Southern Song period quickly exposed the weaknesses of step tapered merlon: it provides less coverage and is vulnerable to the sophisficated stone throwers fielded by Jin armies. As a result, the design was abandoned and replaced by rectangular merlons.

Duo Kou (垛口)

A Duo Kou (empty space between two merlons) on the Great Wall of China. The white-coloured chalk mark on the right merlon was used to record the name of the troop that guarded that specific Duo Kou.

Duo Kou is the Chinese term for crenel. It is also less commonly known as Nu Kou (女口).

Ping Tou Qiang (平頭牆, lit. 'Flattop wall')

Uncrenellated battlement on the ancient town wall of Sanhe, Anhui.

Ping Tou Qiang refers to a rarer type of battlement that has loopholes but not crenellation.

1.2) Towers and bastions

Di Tai (敵臺, lit. 'Opposing platform')

A tower-type Di Tai of the city wall of Taizhou.

Di Tai is a broad term that refers to any fortified tall structure that usually comes with flat roof and battlement, which includes wall towers, bastions, and stand-alone towers not connected to any wall. During Song period it was also known as Nu Tai (弩臺, lit. 'Crossbow platform'), although that name fell out of use.

Di Tai can be further categorised into two types based on its construction: Shi Xin Di Tai (實心敵臺, lit. 'Solid opposing platform'), which is solid and thus has no internal space, and Kong Xin Di Tai (空心敵臺, lit. 'Hollow opposing platform'), which has rooms that allow troops to fight from within it. Generally speaking, tower (i.e. taller than its adjacent walls) tend to be hollow, while bastion (i.e. same height as its adjacent walls) tend to be solid. However, exceptions do exist.

Ma Mian (馬面, lit. 'Horse-face')

Great bastions of the city wall of Pingyao.

Ma Mian is a Chinese term that specifically refers to a rectangular bastion. It is also known as Zhi (雉) and Ying Lou (硬樓, lit. 'Hard tower').

Di Tuan (敵團, lit. 'Opposing round')

Rounded corner bastion at the southwest corner of Xi'an city wall.

Di Tuan is a Chinese term that specifically refers to a round tower or roundel/rounded bastion. It is also known as Tuan Lou (團樓, lit. 'Round tower').

Jiao Tai (角臺, lit. 'Corner platform')

Rectangular corner bastion at the northwest corner of the city wall of Xi'an.

Jiao Tai refers to a Di Tai (whether a tower or a bastion) built at the junction of two walls.

Kong Jun Tai (控軍臺, lit. 'Army commanding platform')

A Kong Jun Tai adjacent to the northwest corner bastion of the rebuilt city wall of Datong.  

Also known as Wang Jun Tai (望軍臺, lit. 'Army lookout platform'), Kong Jun Tai is a stand-alone tower built close to a Jiao Tai. It is the Chinese equivalent of Albarrana tower.

1.3) Superstructures

Cheng Pu (城鋪, lit. 'Wall shack')

A Cheng Pu on the top of one of the bastions of the city wall of Pingyao.

Cheng Pu, also known as Wo Pu (窩鋪, lit. 'Shack'), is a temporary or permanent shelter built on top a city wall or inside the city that primarily functions as accommodation for city watchmen. Permanent version of Cheng Pu, commonly built on bastions, also serve secondary functions as watchtowers and weapon storerooms.

Qi Cheng Pu (騎城鋪, lit. 'Wall-riding shack')

Despite being labelled as Qi Cheng Pu, this illustration seems to depict a normal Cheng Pu. Image taken from 'Wu Bei Zhi (《武備志》)'. 

Also known as Qi Cheng Zou Ma Pu (騎城走馬鋪, lit. 'Wall-riding, horse-walking shack'), Qi Cheng Pu is a special type of Cheng Pu designed for narrow wall with insufficient space for normal-sized Cheng Pu, yet doesn't have bastions. It is essentially a "bridge tower" built on a wall (the wall-walk or chemin de ronde serves as the "bridge"), with a sufficiently large arched gateway to allow defending troops to pass through the tower unhindered. Since the ground floor of the tower is taken up by the gateway, actual living quarters are only located at the first floor and above.

To date, there are no surviving Chinese fortification that can be identified as Qi Cheng Pu.

Di Lou (敵樓, lit. 'Opposing tower')

A guard tower standing on top of one of the bastions of the rebuilt city wall of Datong.

Di Lou can refer to any fortified building (whether temporary or permanent) built on top a wall to protect the defending troops, although in general usage the term is associated almost exclusively with the permanent version, while temporary and semi-permanent defensive structures are refered to as Zhan Peng instead (see below). A permanent Di Lou is also known as Jian Lou (箭樓, lit. 'Arrow tower').

A permanent Di Lou can be distinguished from a Di Tai by its sloped roof and awning, and the fact that it is built on top of a wall or bastion, rather than directly integrated into the wall.

Jiao Lou (角樓, lit. 'Corner tower')

Massive corner tower, essentially fused into the bastion below it, that once guarded the southeast corner of the city wall of Beijing.

Jiao Lou refers to a Di Lou built on the top of a corner bastion. Since corners are the second most vulnerable part of a rectangular fortress after the entrance (as they cannot be supported by friendly troops on the wall on either side), Jiao Lou tend to be heavily fortified, often rivalling the main gate tower of a city.

Que Tai (鵲臺, lit. 'Magpie platform')

Que Tai refers to a raised platform, effectively a secondary wall complete with its own battlement (usually of the Ping Tou Qiang variety) that is usually built on top a primary wall or near the bank of a moat. Originally designed to be an alternative to crenellated battlement to better withstand stone thrower bombardments, walltop Que Tai gradually fell into obsolescence as with the advent of taller, stronger walls and tougher battlements.

1.4) Loopholes and embrasures

Yan (眼, lit. 'Hole')

Square-shaped Duo Yan (垛眼) on the battlement of the Dajin Ge Pavilion of Shanghai.

The Chinese term Yan (眼, eye), when used in this context, refers to various loopholes of a fortification. When referring to a specific type of loophole, extra descriptive words can be simply added before the character Yan. For example, Duo Yan (垛眼, lit. 'Merlon hole') refers to the observation hole on a merlon; Jian Yan (箭眼, lit. 'Arrow hole') refers to arrow loop; Chong Yan (銃眼, lit. 'Gun hole') refers to gun loop; Da Jiang Jun Chong Yan (大將軍銃眼, lit. 'Great general gun hole') refers to large gun loop designed to accommodate Da Jiang Jun Pao (大將軍砲); and Fo Lang Ji Chong Yan (佛狼機銃眼, lit. 'Frankish engine gun loop') refers to medium-sized gun loop for breech-loading swivel gun.

Tian Jing (天井, lit. 'Sky-well')

Close-up of the battlement of the Mutianyu Great Wall section, showing a Duo Yan and two Tian Jing. This image is photoshopped slightly to edit out the tourists.

Tian Jing is one of the few loopholes not called a Yan in Chinese. It refers to a loophole opened at the base of a parapet in-between two merlons to allow stones or other harmful liquid (boiling oil, boiling feces, molten iron etc.) to be dropped/poured onto enemy troops at the base of the wall.

Xuan Yan (懸眼, lit. 'Hanging hole')

Battlement at the rooftop of a guard tower on the Great Wall, equipped with Duo Yan, Xuan Yan and Tian Jing.

Xuan Yan refers to a loophole opened at the base of a parapet in-between two crenels that originally served similar purpose to Tian Jing. Ming general Qi Ji Guang (戚繼光) later improved the design by adding a vertical groove below the loophole, thus allowing the loophole to command the foot of the wall.

Left: Improved Xuan Yan on the Great Wall with a vertical groove, viewed from outside. Right: Looking down through the Xuan Yan.

Jian Chuan (箭窗, lit. 'Arrow window')

Rows of Jian Chuan on the tower of Zhengyang Gate of Beijing.

Jian Chuan is another type of loophole not called a Yan in Chinese. It refers to the large loophole of an enclosed (i.e. roofed) structure such as Di Lou and Di Tai. Despite its name, weapons other than arrow can also be shot out from Jian Chuan.

Generally speaking, Jian Chuan of a Di Lou are equipped with window hatches, while Jian Chuan of a Di Tai are not.

Cang Bing Dong (藏兵洞, lit. 'Troop-concealing cave' or 'Armament-concealing cave')

Several Cang Bing Dong.

A bastion of the city wall of Jingzhou, with visible loopholes in the wall accessible by Cang Bing Dong.

Cang Bing Dong is the Chinese term for casemate.

An Men (暗門, lit. 'Dark door')

Baimajing sally port on the flank of a bastion of Jingzhou city wall. The brick-sealed door was so well-hidden that it was only discovered in 1999 and reopened in 2017.

An Men is the Chinese term for sally port.

1.5) Hoardings

Zhan Peng (戰棚, lit. 'Battle shed')

Hoardings (highlighted) on Weng Cheng and bastions, from 'Wu Bei Zhi (《武備志》)'.

Zhan Peng is the Chinese term for hoarding—temporary or semi-permanent defensive structure built on top of the rampart of a wall, tower, or bastion. It is an unwalled structure (similar to a ramada) with a solid roof made of three foot thick clay mixed with coal, then covered in drenched felt blankets and cowhides to better resist artillery bombardment and fire. In place of the wall, a series of wooden panels known as Xuan Ban (懸板, lit. 'Hanging plank') or Chui Zhong Ban (垂鐘板, lit. 'Drooping bell plank') can be attached to a rail just below the roof to provide protection. Although marginally less protective, Chinese-style hoarding with removable panels has many advantages over ordinary hoarding with fixed walls.

Zhan Peng also comes with floor opening known as Ta Kong Ban (踏空板, lit. 'Misstep plank') that allows the defenders to drop stones and pour burning oil onto enemy below, a feature also presents in European-style castle hoarding and machicolation.

Unfortunately, the taller and thicker Chinese walls, while nearly impervious against direct fire, also present a much larger target for indirect fire weapons, making Zhan Peng particularly vulnerable to stone throwers and gunpowder weaponry. This led to Zhan Peng being phased out relatively early in favour of more permanent Di Lou.

Chuan Lou (串樓, lit. 'Strung tower')

Chuan Lou referst to a type of semi-permanent terraced longhouse built atop a city wall, making full use of the massive size of Chinese walls and their spacious wall-walks/chemins de ronde. It combines the functions of hoarding, guard post, and barrack into one, and allows soldiers to be directly billeted on the wall.

While once relatively common in Ming period Southern China, in particular Guangzhou, Hunan, Jiangxi and Guizhou, no Chuan Lou has survived to the present day.

Bai Lu Wu (白露屋, lit. 'White dew hut')

Drawing of a Bai Lu Wu, from 'Zhan Shou Quan Shu (《戰守全書》)'.

Bai Lu Wu is a small dome-shaped bamboo or willow hut, large enough for a single occupant, built on the roof of Zhan Peng. It serves as a temporary shelter for city watchmen, as well as storage space for firefighting equipment.

Crenel shutter

Drawing of a Xuan Lian in action (left) as well as its construction (right). From 'Zhan Shou Quan Shu (《戰守全書》)'.

Drawing of a Pi Lian (left) and a Xuan Hu (right), from 'Zhan Shou Quan Shu (《戰守全書》)'.

Chinese people also made use of crenel shutter—temporary wooden structure erected during wartime to cover and defend a crenel as well as the troops behind it. Common types of crenel shutters include Xuan Lian (懸簾, lit. 'Hanging curtain'), which uses soaked cotton blanket as cover, Pi Lian (皮簾, lit. 'Leather curtain'), whichs uses carabau hide as cover, and Xuan Hu (懸戶, lit. 'Hanging window'), which uses a wooden shield as cover.

Hu Cheng Zhe Jian Jia (護城遮箭架, lit. 'Wall-protecting, arrow-covering frame')

Two Hu Cheng Zhe Jian Jia, from 'Zhan Shou Quan Shu (《戰守全書》)'.

Hu Cheng Zhe Jian Jia is a special type of crenel shutter that mounts the cover (see above) slightly farther away from the crenel, thus allowing the defending troops to safely lean out from the crenel to attack enemies at the base of the wall.

Bu Man (布幔, lit. 'Cloth curtain')

Drawing of a Bu Man on a pole, from 'Wu Bei Zhi (《武備志》)'.

Bu Man is a large protective curtain made of multiple layers of thick clothes (or alternatively, multiple layers of nets) that hangs from a wooden pole. The pole can be mounted on the wall to give the defenders an extra layer of protective screen.

Mobile version of Bu Man is known as Mu Man (木幔).

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