Attack by Stratagem

This is the chapter of the book's most famous idea: the highest skill is not winning battles but winning without them. "In the practical art of war, the best thing of all is to take the enemy's country whole and intact; to shatter and destroy it is not so good." To capture an army entire is better than to destroy it; to take a regiment, a company, or a squad whole is better than to crush it. "Hence to fight and conquer in all your battles is not supreme excellence; supreme excellence consists in breaking the enemy's resistance without fighting."

Sun Tzu ranks the methods of war in descending order of merit. The highest form of generalship is to baulk the enemy's plans; the next is to prevent the junction of his forces by breaking his alliances; the next is to attack his army in the field; and the worst policy of all is to besiege walled cities, which should be undertaken only when unavoidable. Sieges devour months in preparing engines and mounds, and an impatient general who hurls his men against the walls "like swarming ants" loses a third of them with the town still untaken — "the disastrous effect of a siege."

The skillful leader, therefore, subdues the enemy's troops without fighting, captures cities without laying siege, and overthrows kingdoms without lengthy operations. With his forces intact he contests the mastery of the empire, "and thus, without losing a man, his triumph will be complete."

He then gives rules of force ratios: if ten to the enemy's one, surround him; if five to one, attack him; if twice as numerous, divide your army in two; if equally matched, offer battle; if slightly inferior, be able to avoid him; if quite unequal, flee. A small force that fights obstinately against a larger one is simply captured.

The chapter names five essentials for victory: knowing when to fight and when not to fight; knowing how to handle both superior and inferior forces; an army animated by the same spirit through all its ranks; being prepared and waiting to take the enemy unprepared; and a capable general unhampered by interference from the sovereign. It closes with the line that became the book's signature: "If you know the enemy and know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat. If you know neither the enemy nor yourself, you will succumb in every battle." Self-knowledge and intelligence, not mere force, decide the outcome.