The Art of War Summary by Chapter | Sun Tzu

Key Insight: Sun Tzu’s treatise is a distillation of personal observation and experience that has influenced military leaders for over two millennia.

Chapter 2: Laying Plans

This chapter defines the foundational variables that determine victory before any battle begins. Success can be forecasted through the analytical comparison of five constant factors and seven essential considerations.

The five factors are Moral Law (ensuring the people are in accord with their ruler), Heaven, Earth, the Commander (wisdom, sincerity, courage, strictness), and Method and Discipline. All warfare is based on deception, requiring the general to feign inactivity and distance.

If an opponent is of “choleric temper,” one should seek to irritate him. The general who makes many calculations in his temple before the fight is the one who wins. Military devices leading to victory must never be divulged beforehand.

Key Insight: The general who wins a battle makes many calculations in his temple before the fight is even joined.

Chapter 3: Waging War

This chapter focuses on the economic and logistical realities of maintaining a military force. Time is more valuable than numerical superiority, as “cleverness has never been seen associated with long delays.”

An army of 100,000 men costs a thousand ounces of silver per day. Protracted campaigns damp ardor, dull weapons, and exhaust the State’s treasury. The skillful soldier forages on the enemy, as one cartload of enemy provisions is worth twenty from home.

Captured soldiers should be treated kindly and utilized to “augment one’s own strength.” The “leader of armies” is the arbiter of the nation’s fate. Let your great object be victory, not lengthy campaigns.

Key Insight: In war, let your great object be victory, not lengthy campaigns.

Chapter 4: Attack by Stratagem

Supreme excellence consists in breaking the enemy’s resistance without fighting. The hierarchy of strategy: first balk the enemy’s plans, then prevent the junction of their forces, then attack the army, and lastly besiege cities.

The worst policy is to besiege walled cities, which takes months and causes immense slaughter. The rule of ten to one dictates when to surround, attack, or divide forces based on numerical ratios.

If you know the enemy and know yourself, you need not fear the result of a hundred battles. Five essentials for victory include knowing when to fight and when not to fight, and having a sovereign who does not interfere with the army’s operations.

Key Insight: If you know the enemy and know yourself, you need not fear the result of a hundred battles.

Chapter 5: Tactical Dispositions

Security against defeat lies in our own hands; the chance to defeat the enemy is provided by the enemy’s own mistakes. A clever fighter wins with ease, meaning his victories bring him neither reputation for wisdom nor credit for courage.

The “ninth earth” hides defense; the “topmost heights of heaven” flashes forth in attack. A victorious army is a “pound’s weight” against a “single grain.” Making no mistakes establishes the certainty of victory.

The consummate leader cultivates Moral Law and adheres to discipline to control success. A five‑step method leads from measurement to victory: Measurement, Estimation, Calculation, Balancing of chances, and Victory.

Key Insight: Making no mistakes is what establishes the certainty of victory.

Chapter 6: Energy

Control of a large force is the same principle as control of a few men, requiring only proper subdivision and signals. The “Cheng” (direct) and “Ch’i” (indirect) methods of attack combine in endless variations.

Cheng is used for joining battle, but Ch’i is needed to secure victory. A clever combatant looks to the effect of combined energy rather than requiring too much from individuals.

The energy developed by good fighting men is as the momentum of a round stone rolled down a mountain. Hide order beneath the cloak of disorder, and simulate weakness to postulate strength.

Key Insight: The energy developed by good fighting men is as the momentum of a round stone rolled down a mountain.

Chapter 7: Weak Points and Strong

Avoid what is strong and strike at what is weak to ensure irresistibility in every move. Remain invisible while forcing the enemy to divide their forces to guard multiple points.

The clever combatant imposes his will on the enemy. Numerical weakness comes from having to prepare against possible attacks; victory can be achieved even against superior numbers if the enemy is kept ignorant of the time and place of battle.

Military tactics are like water, which shapes its course according to the nature of the ground. The highest pitch of tactical dispositions is total concealment from the prying of spies. There are no constant conditions in warfare.

Key Insight: Military tactics are like unto water, which shapes its course according to the nature of the ground.

Chapter 8: Maneuvering

Turn the devious into the direct by enticing the enemy out of the way to reach a goal before them. Gongs, drums, and flags focus the host’s eyes and ears, enabling the art of handling large masses.

An army without its baggage train is lost. Avoid an army when its spirit is keen; instead, wait for its energy to decline. When surrounding an enemy, leave an outlet free to prevent them from fighting with the courage of despair.

In war, practice dissimulation, and you will succeed. Study moods and husband strength. A commander‑in‑chief may be robbed of his presence of mind if the general is clever.

Key Insight: In war, practice dissimulation, and you will succeed.