Chapter 1 — Laying Plans
Laying Plans
Chapter 1 is the foundation of the entire treatise. Sun Tzu opens with the claim that war is a matter of vital importance to the state — a matter of life and death, survival or destruction — and that it demands serious study. Five fundamental factors govern every military situation: Moral Authority (the alignment of the people with their leader), Heaven (timing and the seasons), Earth (terrain and distance), Leadership (the commander's character), and Method and Discipline (organization, supply, command). Seven comparative questions follow — on authority, competence, terrain, discipline, strength, training, and consistency of reward and punishment — through which victory or defeat can be predicted before the campaign begins. The chapter closes with the doctrine that will govern everything that follows: all warfare is based on deception. Appear unable when able. Appear passive when active. Strike where the enemy is not prepared. Appear where he does not expect. These principles that lead to victory, Sun Tzu says, must never be revealed in advance.
Chapter 2 — Waging War
Waging War
Chapter 2 is the treatise's accounting. A major military operation — a thousand fast chariots, a thousand heavy chariots, a hundred thousand armored soldiers, supply trains stretching hundreds of miles — imposes an enormous burden on the state. When victory takes too long, troops grow weary, morale collapses, the treasury empties, and rival powers move in. Speed is essential. No nation has ever benefited from a prolonged war. The chapter's practical doctrine follows: live off the enemy's land whenever possible, reward soldiers who seize the enemy's resources, and turn captured resources into your own strength. The goal is decisive victory, not the drawn-out campaign. The commander of an army holds the fate of the people in his hands — he determines whether the nation lives in peace or fails.
Chapter 3 — Attack by Stratagem
Attack by Stratagem
Chapter 3 is the heart of the treatise. The doctrine at the centre: it is better to capture the enemy's territory intact than to destroy it; better still to break his resistance without destroying anything at all. There is a hierarchy. The highest form of warfare is to defeat the enemy's strategy before he can act on it. The next is to break apart his alliances. The next is to attack his army in the field. The last and worst is to besiege his fortified cities. The chapter then gives the five keys to victory — knowing when to fight and when to hold back; knowing how to deploy both large and small forces; unified purpose throughout the organization; preparation against an unprepared enemy; military competence unconstrained by political micromanagement. It closes with the formula every reader knows: know the enemy and know yourself.
Chapter 4 — Tactical Dispositions
Tactical Dispositions
Chapter 4 works the relation between invincibility and vulnerability. Making yourself unbeatable is within your control; whether the enemy gives you an opening is up to him. The chapter introduces a key distinction: defense signals insufficient strength; attack signals overwhelming strength. The master of defense hides so thoroughly that he cannot be found. The master of attack strikes from an unexpected direction with overwhelming force. The brilliant fighter's victories earn him no reputation for genius — because they look easy. They look easy because he won before the battle was joined, by configuring his forces so that victory was already implicit in the form. The chapter closes with an account of how military method works: measurement from terrain, assessment from measurement, calculation from assessment, comparison from calculation, victory from comparison.
Chapter 5 — Energy
Energy
Chapter 5 extends the ideas of Chapter 4 from configuration to force. The direct approach is used to engage the enemy; the indirect is what delivers victory. The combinations of direct and indirect are as infinite as the combinations of five musical notes or five primary colors — the basic elements are few, but their interaction generates endless variety. Sun Tzu's central image: momentum is like a torrent powerful enough to roll boulders downstream. Energy is like drawing a crossbow; timing is like releasing the bolt. Ferocity in momentum and precision in timing — these are the marks of the great fighter. The chapter closes by returning to the boulder: when you harness combined momentum, soldiers become like boulders on a slope. A boulder sits still on flat ground, but when the configuration is right and the moment comes, the stone rolls and nothing stops it.
Chapter 6 — Weak Points and Strong
Weak Points and Strong
Chapter 6 is the operational extension of the deception doctrine from Chapter 1 and the most concentrated treatment in the book of the principle of initiative. The skilled fighter imposes his will on the enemy and never allows the enemy to impose its will on him. By offering advantages, he draws the enemy to where he wants them; by threatening damage, he keeps them away. Strike where the enemy is unprepared. Move where he does not expect. Appear at positions he must rush to defend. March swiftly to places he cannot anticipate. Concentrate your forces while the enemy must scatter his; pit your whole against his parts. The chapter closes with its most famous image: military strategy is like water — it flows away from strength and toward weakness, shapes its course according to the terrain, has no fixed form. The commander who can do the same is the one the book calls a genius.
Chapter 7 — Maneuvering
Maneuvering
Chapter 7 descends from doctrine to the operational realities of moving armies. Maneuvering is the most difficult part of warfare because it requires turning indirect routes into direct ones and setbacks into advantages. The chapter's warnings are practical and severe: if you send your full army to seize an advantage, you arrive too late; if you send a fast detachment, it will travel light but lose its supply train. Force-march your troops beyond sustainable distances for any objective, and only a fraction of your force will arrive — the strongest first, the weakest never. Without supply, without provisions, without secure bases, an army is lost. The chapter then gives the principles of the moving army: fast as wind, steady as forest, devastating as fire, immovable as mountain, dark as night, striking like thunder. And it closes with a section on the management of morale: avoid the enemy when their spirit is high; attack when they are sluggish. Maintain your own composure while the enemy falls into disorder. Rest while they exhaust themselves.
Chapter 8 — Variation in Tactics
Variation in Tactics
Chapter 8 is the shortest substantive chapter in the book and one of the most important. The premise: a commander who knows the advantages of tactical flexibility knows how to deploy troops effectively. One who does not — even if he knows the terrain perfectly — will fail to turn that knowledge into results. The chapter gives a series of rules that function as negations of the obvious: some roads should not be taken; some armies should not be attacked; some cities should not be besieged; some positions should not be contested; some sovereign's orders should not be followed. The wise leader always weighs both advantage and disadvantage together. The chapter closes with the five dangerous character flaws of a commander: recklessness; cowardice; a quick temper; over-sensitivity to shame; over-attachment to his troops. These five flaws are fatal. When an army is destroyed and its leader killed, the cause will always trace back to one of them.
Chapter 9 — The Army on the March
The Army on the March
Chapter 9 is the most concrete chapter in the treatise — specific about terrain, observation, and the reading of signals. Four major terrain types receive their rules: mountains, rivers, marshes, and flat ground. The rules are precise: cross mountains quickly and stay near valleys; when the enemy crosses a river toward you, let half their army cross before you attack; in marshes, get through them fast with trees at your back. The chapter then turns to the reading of enemy signals — the most famous passage in this section: birds suddenly taking flight signals an ambush; startled animals mean a surprise attack is coming; dust rising in a tall column signals chariots; dust spread low and wide signals infantry. The chapter closes on the principles of command: treat soldiers with respect and then hold them to iron discipline. Genuine confidence combined with insistence on obedience is the proven path to mutual loyalty.
Chapter 10 — Terrain
Terrain
Chapter 10 classifies terrain into six types — accessible, entangling, stalemate, narrow-pass, cliff-and-height, and distant — and gives the rule for each. Accessible ground: occupy the high, sunny positions first. Entangling ground: if the enemy is unprepared, strike; if prepared, retreat is difficult and pursuit leads to disaster. Stalemate ground: even if the enemy offers tempting bait, do not advance. The chapter then turns from terrain to command failure, classifying six types: flight (a force thrown against one ten times its size), insubordination (soldiers too aggressive, officers too weak), collapse (officers overbearing, soldiers passive), ruin (senior officers resentful and insubordinate), disorganization (the commander weak and unclear), and rout (sending a small force against a large one). The chapter closes with the principle that unifies both classifications: terrain is a soldier's greatest ally, but the ability to assess the enemy, control the conditions for victory, and accurately judge the difficulty of the terrain is what separates the general who wins from the one who loses.
Chapter 11 — The Nine Situations
The Nine Situations
Chapter 11 is the longest in the treatise — more than twice the length of Chapter 12 — and the most comprehensive. Nine types of ground receive their classifications and their doctrines: dispersive (your own territory), frontier (barely entered enemy territory), contested (high-value for both sides), open (free movement both ways), crossroads (junction of three territories), serious (deep penetration), difficult (mountains, marshes, swamps), enclosed (narrow approaches, winding retreat), and death (survival requires fighting immediately). The rules for each follow. The chapter then elaborates the psychology of desperate situations: soldiers placed in positions without escape will choose death over flight, lose their fear, and fight with everything they have. The great commander seizes something the enemy values most, forces him to respond, and controls when and where the battle happens. The chapter closes with its most famous image: the shuai-jan snake — strike the head, the tail attacks; strike the tail, the head attacks; strike the middle, both attack. Can an army be made to act like this? Yes.
Chapter 12 — The Attack by Fire
The Attack by Fire
Chapter 12 treats incendiary attack as the most dramatic force-multiplier available to the ancient commander and uses it as the vehicle for one of the book's deepest ethical conclusions. The five types of fire attack: burn the enemy's troops in camp; burn their supplies; burn their equipment depots; burn their supply lines; use fire to create disorder. The conditions must be right — dry weather, rising winds — and the commander must understand the five possible developments of a fire attack and respond to each correctly. Fire demonstrates intelligence; water demonstrates additional force. But the chapter closes not on tactics but on restraint. Do not move unless there is a clear advantage. Do not fight unless there is something to win. Do not start a war out of anger; do not fight a battle out of spite. Anger fades. Irritation passes. But a destroyed nation cannot be rebuilt, and the dead cannot be brought back to life.
Chapter 13 — The Use of Spies
The Use of Spies
Chapter 13 is the closing chapter of the treatise and functions as its manifesto. The argument begins with the accounting from Chapter 2: raising a hundred thousand men and marching them great distances disrupts hundreds of thousands of households. To stake the outcome of all this on the day of battle — when the outcome could be tilted decisively by foreknowledge of the enemy's dispositions — is to be foolish past forgiveness. The foreknowledge cannot come from supernatural sources, from inference, from analogy, or from divination. It can only come from people. There are five types of spies: local, inside, turned, expendable, and surviving. When all five types are working simultaneously, the system becomes impenetrable — what Sun Tzu calls the divine web, the sovereign's most precious instrument. The chapter closes with the claim that the entire ability of an army to act depends on the intelligence the spies provide. Spies are the most critical element in warfare, and the enlightened ruler who uses them well will achieve what ordinary people cannot.