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

sufficient; it only means that no direct attack can be made. [Literally, "no martial advance." That is to say, _cheng_ tactics and frontal attacks must be eschewed, and stratagem resorted to instead.] What we can do is simply to concentrate all our available strength, keep a close watch on the enemy, and obtain reinforcements. [This is an obscure sentence, and none of the commentators succeed in squeezing very good sense out of it. I follow Li Ch’uan, who appears to offer the simplest explanation: "Only the side that gets more men will win." Fortunately we have Chang Yu to expound its meaning to us in language which is lucidity itself: "When the numbers are even, and no favourable opening presents itself, although we may not be strong enough to deliver a sustained attack, we can find additional recruits amongst our sutlers and camp-followers, and then, concentrating our forces and keeping a close watch on the enemy, contrive to snatch the victory. But we must avoid borrowing foreign soldiers to help us." He then quotes from Wei Liao Tzŭ, ch. 3: "The nominal strength of mercenary troops may be 100,000, but their real value will be not more than half that figure."]