The Art of War by active 6th century B.C. Sunzi

1. Sun Tzŭ said: We come now to the question of encamping the army, and

observing signs of the enemy. Pass quickly over mountains, and keep in the neighbourhood of valleys. [The idea is, not to linger among barren uplands, but to keep close to supplies of water and grass. Cf. Wu Tzŭ, ch. 3: "Abide not in natural ovens," i.e. "the openings of valleys." Chang Yu tells the following anecdote: Wu-tu Ch’iang was a robber captain in the time of the Later Han, and Ma Yuan was sent to exterminate his gang. Ch’iang having found a refuge in the hills, Ma Yuan made no attempt to force a battle, but seized all the favourable positions commanding supplies of water and forage. Ch’iang was soon in such a desperate plight for want of provisions that he was forced to make a total surrender. He did not know the advantage of keeping in the neighbourhood of valleys."]