Chapter 53
備高臨
Defense against Attack from an Elevation
禽子再拜再拜曰：「敢問適人積土為高，以臨吾城，薪土俱上，以為羊黔，蒙櫓俱前，遂屬之城，兵弩俱上，為之柰何？」
Master Qin bowed repeatedly and said: 'May I ask what is to be done when the enemy piles up earth to make a high mound in order to approach our wall, places firewood and earth on top to make a yangqian (high mound) and after covering it with shields at the front, sets it up against the wall with [soldiers carrying] weapons and crossbows on top of it?'
子墨子曰：「子問羊黔之守邪？羊黔者將之拙者也，足以勞卒，不足以害城。守為臺城，以臨羊黔，左右出巨，各二十尺，行城三十尺，強弩射之，技機藉之，奇器口口之，然則羊黔之攻敗矣。
Master Mo replied: 'Are you asking about the defence against the yangqian? Those who would use such a ramp are stupid. [It is a device] which is sufficient to wear out the soldiers, but not sufficient to harm the city. In defence, make 'terrace walls' and bring them adjacent to the yangqian. On the left and right, project rams, each 20 chi in length. The movable walls should be 30 chi high; powerful crossbows are fired from them. If you make use of these ingenious devices, the yangqian attack can be defeated.'
備臨以連弩之車材大方一方一尺，長稱城之薄厚。兩軸三輪，輪居筐中，重下上筐。左右旁二植，左右有衡植，衡植左右皆圜內，內徑四寸。左右縳弩皆於植，以弦鉤弦，至於大弦。弩臂前後與筐齊，筐高八尺，弩軸去下筐三尺五寸。連弩機郭同銅，一石三十鈞。引弦鹿長奴。筐大三圍半，左右有鉤距，方三寸，輪厚尺二寸，鉤距臂博尺四寸，厚七寸，長六尺。橫臂齊筐外，蚤尺五寸，有距，博六寸，厚三寸，長如筐，有儀，有詘勝，可上下。為武重一石以材大圍五寸。矢長十尺，以繩系箭矢端，如如戈射，以磿鹿卷收。矢高弩臂三尺，用弩無數，出人六十枚，用小矢無留。十人主此車。遂具寇，為高樓以射道，城上以荅、羅，矢。
In preparing against the high and adjacent, use the 'joined crossbow' carriage (liannu che). [This is made of] timbers 1 chi square and is of a length corresponding to the wall's thickness. It has two axles and four wheels, the wheels being inside the frame. The inside itself is divided into upper and lower levels. Both left and right sides have two vertical posts each, and left and right sides have a horizontal beam. The left and right ends of both horizontal beams all have a tenon which projects straight out for 4 cun. To the left and right the crossbows are all bound to the vertical posts. All the strings, right up to the main string, are linked together with a 'tooth'. The crossbow 'arm' (?stock) at the front and back is level with the frame [of the carriage] which is 8 chi high. The crossbow pivot extends 3 chi and 5 cun below the frame. The 'joined crossbow' (lian nu) control mechanism and its housing are made of bronze [requiring] 1 dan and 30 jin. The string is drawn around a windlass. The size of the frame is 3 1/2 wei (spans). To the left and right there are 'teeth' 3 cun square. The wheels [of the cart] are 1 chi 2 cun thick. The 'arms' for the 'teeth' are 1 chi 4 cun wide, 7 cun thick and 6 chi long. External to the 'arms' and level with the frame there is a 'claw' which is 1 chi 5 cun long and extends transversely on both sides. It is 6 cun wide, 3 cun thick and of the same length as the frame. There is an aiming mechanism which is able to rise or fall and can be directed upwards or downwards. The base of the crossbow should weigh 1 dan and be made from timbers 1 wei 5 cun in size. The arrows are 10 chi long and have a cord attached to the end like a yishe (arrow firer) which can be wound back by a windlass. The arrows extend above the crossbow 'arms' by 3 chi. There is no limit to the number of crossbows. Sixty [large arrows] are fired and retrieved, whereas small arrows are not retrieved. Ten men control this cart. When an attack is seen, the enemy can be fired at from the high towers, while on the wall a protective screen is used against enemy arrows.