Chapter 53: Preparations Against High Platforms
Qinzi bowed twice and said, “May I ask, if the enemy piles up earth to build a high platform to overlook our city, carrying up firewood and earth together to construct a ‘Yangqian’ (sheep mound), advancing with covered shields and carts right up to our walls, with soldiers and crossbows attacking from above, what should we do?”
Master Mo said, “Are you asking about defending against the Yangqian? The Yangqian is a clumsy tactic of a commander. It is sufficient only to exhaust the soldiers, but not enough to harm the city. To defend against it, build a high platform (Tai Cheng) inside the city to overlook the enemy’s Yangqian. Extend it twenty chi on both the left and right sides, with a connecting wall (Xing Cheng) thirty chi long. Shoot at them with strong crossbows, and use ingenious mechanical devices against them; thus, the attack of the Yangqian will be defeated.
To defend against high platforms, use linked crossbow carts (Lian Nu Zhi Che). The timber for the cart should be one chi square in cross-section, and its length should correspond to the thickness of the city wall. It has two axles and three wheels, with the wheels placed inside the cart frame; the bottom is heavy and the top frame is light. On the left and right sides of the frame, there are two vertical posts, and horizontal posts on both sides. The ends of the horizontal posts are round, with an inner diameter of four cun. The crossbows on the left and right are tied to the posts, with hooks connecting the bowstrings to the main string. The crossbow arms are level with the front and back of the cart frame, which is eight chi high. The crossbow axle is three chi five cun above the bottom of the frame. The trigger mechanism and the outer frame of the linked crossbow are made of the same bronze, weighing one shi and thirty jun. A winch (Lu Chang Nu) is used to pull and wind the string. The cart frame is three and a half wei in circumference, with hook brackets on the left and right, three cun square. The wheels are one chi two cun thick. The arms of the hook brackets are one chi four cun wide, seven cun thick, and six chi long. The horizontal arms are level with the outside of the frame, with a protruding end one chi five cun long, equipped with a stopper six cun wide and three cun thick, as long as the frame. There is a sighting instrument (Yi) with an adjustable mechanism that can move up and down. The body of the crossbow weighs one shi and is made of timber five cun in circumference. The arrows are ten chi long, with a rope attached to the end. They are shot like a ge (dagger-axe) and wound back using the winch. The arrows stand three chi higher than the crossbow arm. There is no limit to the number of arrows used; sixty arrows can be loaded and fired at once. If small arrows are used, they do not need to be recovered. Ten men are required to operate this cart.
When the enemy launches a full-scale attack, build high towers to shoot down at them, and use wooden or wicker shields (Da) on the city walls to block their arrows.”
Note
This chapter records Mozi’s response to disciple Qin Guli on countering enemy earthen siege mounds. It details tall inner counter towers and giant multi-shot linked crossbow carts with winch mechanisms for repelling elevated assaults.
Qin Guli (禽滑厘 / Qinzi / Qin Huali):
A primary disciple and eventual successor of Mozi. In the Mozi, he frequently serves as the interlocutor asking technical and strategic questions regarding Mohist defensive warfare, representing the practical, engineering-oriented side of the Mohist school.
Yangqian (羊黔 / Sheep Mound):
An ancient siege tactic where attackers piled up earth and wood to build a platform higher than the city walls, allowing them to shoot down into the city. Mozi dismisses this as a “clumsy” tactic because it requires immense labor and time, making it vulnerable to counter-siege measures.
Linked Crossbow Cart (连弩车):
This chapter provides one of the earliest and most detailed technical descriptions of a massive, multi-arrow crossbow mechanism in Chinese history. The cart features a bronze trigger, a winch system for drawing the heavy string, and a rope-retrieval system for the arrows. This highlights the advanced mechanical engineering and standardized manufacturing of the Mohists.
Tai Cheng (台城 / High Platform):
Demonstrates the Mohist principle of “meeting force with force” in siege warfare. Rather than just passively defending, defenders were instructed to build their own elevated platforms inside the city to neutralize the enemy’s height advantage.
Lu Chang Nu (鹿长奴):
A phonetic transcription referring to a winch or windlass used to draw the heavy bowstring of the linked crossbow. It showcases the specialized technical vocabulary developed by ancient Chinese military engineers.
Da (荅):
A type of large, movable shield made of wood or woven wicker, used to protect defenders on the walls from incoming arrows. It reflects the practical, low-cost defensive adaptations favored by the Mohists.
53章 备高临
禽子再拜再拜曰：“敢问适人积土为高，以临吾城，薪土俱上，以为羊黔，蒙橹俱前，遂属之城，兵弩俱上，为之奈何？”
子墨子曰：子问羊黔之守邪？羊黔者，将之拙者也，足以劳卒，不足以害城。守为台城，以临羊黔，左右出巨，各二十尺，行城三十尺，强弩之，技机藉之，奇器口口之，然则羊黔之攻败矣。
备临以连弩之车，材大方一方一尺，长称城之薄厚。两轴三轮，轮居筐中，重下上筐。左右旁二植，左右有衡植，衡植左右皆圜内，内径四寸。左右缚弩皆于植，以弦钩弦，至于大弦。弩臂前后与筐齐，筐高八尺，弩轴去下筐三尺五寸。连弩机郭同铜，一石三十钧。引弦鹿长奴。筐大三围半，左右有钩距，方三寸，轮厚尺二寸，钩距臂博尺四寸，厚七寸，长六尺。横臂齐筐外，蚤尺五寸，有距，搏六寸，厚三寸，长如筐有仪，有诎胜，可上下，为武重一石，以材大围五寸。矢长十尺，以绳矢端，如戈射，以磨鹿卷收。矢高弩臂三尺，用弩无数，出人六十枚，用小矢无留。十人主此车。
遂具寇，为高楼以射道，城上以荅罗矢。
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