墨子 MOZI

Within the wall, but outside the trench, make an encircling road 8 bu wide. In preparing against water (flooding), make a careful estimation of the height of the ground at all points. Where the ground within the wall is sloping down (low), create a tile-lined channel in it extending to low ground. Wells should be dug at the deepest places in the ground. Then place a measuring tile in each well and when the depth of the water outside exceeds 1 zhang, dig water channels within the wall.

Boats are joined together in pairs to make 10 lin ('approachers'), each 'approacher' having thirty men. Each man is in charge of a crossbow and four of every ten men have a youfang. It is necessary for those skilled in boats to make fenwen ('tanks'). Twenty such craft constitute a 'squadron'. Thirty men, capable and strong, are chosen for each craft. Of these, twelve men wield a youfang and wear armour and leather helmets, while the other eighteen men have a miao. Before training these capable soldiers, their parents, wives and children are held as hostages at a different place and provided for. When it is seen that the waters (dikes) can be breached, use the lin and fenwen to breach the outside (enemy) dikes, assisting them with rapid fire from the 'revolving shooting machines' (rotating crossbows) on the wall.