The Art of War by Sun Tzu (All 13 chapters)

The Art of War by Sun Tzu, also known as The Military Classic, The Classic of Warfare, Sun Wu’s Art of War, or Wu’s Sun Tzu Art of War, is an ancient Chinese military treatise authored by Sun Wu, a native of the Qi state during the late Spring and Autumn period. The book is divided into thirteen chapters:

Chapter 1: Laying Plans

Sun Tzu said:

Warfare is a matter of vital importance to the state, a matter of life and death, survival or ruin. It must be thoroughly examined.

Thus, evaluate it through five factors and assess their conditions through comparisons:

1. Dao (Moral Influence): The harmony between ruler and people, enabling them to face death or life without fear of danger.
2. Heaven: The cycles of yin and yang, cold and heat, and the constraints of seasons.
3. Earth: Distances, terrain difficulty, open or confined spaces, and areas of life or death.
4. General: Wisdom, trustworthiness, benevolence, courage, and strictness.
5. Law: Organization, chain of command, and resource management.

Every general knows these five factors. Those who understand them win; those who do not, lose.

Thus, compare and assess: Which ruler has the moral influence? Which general has ability? Who has the advantage of heaven and earth? Whose laws and orders are enforced? Whose troops are stronger? Whose soldiers are better trained? Whose rewards and punishments are clearer? From these, I can determine victory or defeat.

A general who heeds my strategies will win and should be retained; one who ignores them will lose and should be dismissed.

When strategies are advantageous, create momentum to support external efforts. Momentum arises from seizing opportunities.

Warfare is the way of deception.

Thus, appear incapable when capable, inactive when active, near when far, far when near.

Lure with benefits, seize amid chaos, prepare against strength, avoid the powerful, provoke the angry, humble the arrogant, tire the rested, divide the united, attack the unprepared, and strike where unexpected.

This is the strategist’s path to victory, which cannot be taught in advance.

Those who calculate thoroughly in the temple before battle and secure many advantages win; those with few calculations lose. How much worse for those with none? Through this lens, victory or defeat is clear.

Chapter 2: Waging War

Sun Tzu said:

The method of warfare requires a thousand swift chariots, a thousand heavy chariots, and a hundred thousand armored troops, with provisions transported over a thousand miles. Internal and external expenses, envoy costs, materials like glue and lacquer, and chariot and armor maintenance cost a thousand gold pieces daily. Only then can an army of a hundred thousand be mobilized.

In war, prioritize swift victory. Prolonged campaigns dull weapons, sap morale, exhaust strength in sieges, and deplete national resources.

When weapons are dulled, strength exhausted, and wealth drained, neighboring states exploit the weakness, and even the wisest cannot recover.

Thus, in war, clumsy speed is better than prolonged cleverness. No state has ever prospered from extended warfare.

Those unaware of war’s costs cannot fully grasp its benefits.

A skilled general avoids repeated conscription and multiple grain shipments, using resources from the state and capturing provisions from the enemy to sustain the army.

Distant supply lines impoverish the state and its people. Near armies, prices rise, draining wealth and forcing heavy taxation.

Strength and wealth exhausted, the heartland weakens, households lose seven-tenths of their wealth, and the state loses six-tenths of its resources on broken chariots, worn horses, armor, arrows, crossbows, halberds, shields, and supply wagons.

Thus, a wise general feeds off the enemy. One bushel of enemy provisions is worth twenty of our own; one picul of enemy fodder equals twenty of ours.

To kill the enemy, rouse your troops’ anger. To seize enemy resources, offer rewards.

In chariot battles, reward the first to capture ten or more chariots, replace their banners, integrate their vehicles, and treat captured soldiers well. This is how to defeat the enemy and grow stronger.

Thus, war values victory, not duration.

A general who understands warfare is the arbiter of the people’s fate and the key to the state’s safety or peril.

Chapter 3: Attack by Stratagem

Sun Tzu said:

In warfare, preserving the enemy state intact is best; destroying it is secondary. Preserving an enemy army is best; destroying it is secondary. Preserving a battalion, company, or squad is best; destroying them is secondary.**Thus, winning a hundred battles is not the pinnacle of skill. Subduing the enemy without fighting is the ultimate excellence.

The best strategy is to attack the enemy’s plans, next to disrupt their alliances, then to engage their army, and the worst is to besiege their cities. Sieging is a last resort.

Building siege equipment and preparing for an assault takes three months, and scaling walls another three. If a general, unable to control his frustration, orders a reckless assault, he loses a third of his troops without taking the city—a disaster in siege warfare.

Thus, a skilled general subdues the enemy without battle, captures cities without assault, and destroys states without prolonged campaigns.

The goal is to contend for supremacy intact, preserving both forces and benefits. This is the method of strategic attack.

In warfare: Surround when ten times stronger, attack when five times stronger, divide when twice as strong. If equal, fight if possible; if fewer, evade; if weaker, avoid. A small force’s stubbornness leads to its capture by a larger one.

The general is the state’s support. A capable general strengthens the state; a flawed one weakens it. Three ways a ruler harms the army:

1. Ordering advance or retreat when inappropriate, shackling the army.
2. Meddling in military affairs without understanding them, confusing the troops.
3. Interfering in military appointments without understanding their authority, sowing doubt.When the army is confused and doubtful, neighboring states exploit the chaos, leading to defeat.Five ways to foresee victory:
4. Knowing when to fight and when not to.
5. Understanding how to use forces, large or small.
6. Uniting ruler and troops in shared purpose.
7. Being prepared to face an unprepared enemy.
8. Having capable generals free from ruler interference.

These are the paths to victory.

Thus: Know the enemy and yourself, and you will not be imperiled in a hundred battles. Know yourself but not the enemy, and you win half the time. Know neither, and every battle brings defeat.

Chapter 4: Tactical Dispositions**

Sun Tzu said:

Skilled warriors first make themselves invincible, then await the enemy’s vulnerability. Invincibility lies within oneself; vulnerability lies with the enemy.

A skilled warrior can ensure invincibility but cannot guarantee the enemy’s vulnerability.

Thus, victory can be foreseen but not forced.

Invincibility is defense; vulnerability is attack.

Defend when resources are insufficient; attack when they are abundant.

Skilled defenders hide beneath the earth’s depths; skilled attackers strike from the heavens’ heights, achieving self-preservation and complete victory.

Seeing victory no greater than common knowledge is not the pinnacle of skill. Winning battles praised by all is not the pinnacle of skill.

Lifting a hair is not strength, seeing the sun and moon is not keen vision, hearing thunder is not sharp hearing.

Ancient skilled warriors triumphed over easily defeated enemies. Their victories bore no fame for wisdom or courage, as they were flawless, defeating already beaten foes.

Skilled warriors stand on undefeatable ground and never miss the enemy’s defeat.

Victorious armies win first, then fight; defeated armies fight first, then seek victory.

Skilled generals cultivate moral influence and uphold discipline, controlling victory or defeat.

Military principles: Measurement, Estimation, Calculation, Balancing, and Victory.

Terrain yields measurement, measurement yields estimation, estimation yields calculation, calculation yields balancing, and balancing yields victory.

A victorious army is like a pound against a grain; a defeated army is like a grain against a pound.

The victorious army’s assault is like water bursting from a thousand-foot gorge—this is disposition.

Chapter 5: Energy

Sun Tzu said:

Managing many is like managing few—through organization.

Fighting many is like fighting few—through signals and names.

Ensuring an army withstands enemy attacks without defeat lies in combining orthodox and unorthodox tactics.**Striking with the force of a stone shattering an egg relies on exploiting emptiness and solidity.

In battle, engage with orthodox methods, win with unorthodox ones. Skilled commanders wield unorthodox tactics endlessly, like heaven and earth, inexhaustible as rivers.

They cycle like the sun and moon, die and are reborn like the seasons.

There are but five notes, yet their variations are infinite to the ear.

There are but five colors, yet their variations are boundless to the eye.

There are but five tastes, yet their variations are endless to the palate.

In warfare, tactics are either orthodox or unorthodox, yet their combinations are infinite. Orthodox and unorthodox generate each other, like a cycle without end—who can exhaust them?

The rush of water that moves stones is momentum. The strike of a hawk that breaks its prey is timing. Skilled warriors create perilous momentum and precise timing.

Their momentum is like a drawn crossbow; their timing is like the release of the trigger.

Amid chaos and disorder, they remain unconfused. In turmoil, their formations hold, undefeatable.

Order arises from chaos, courage from fear, strength from weakness.

Order or chaos depends on organization; courage or fear on momentum; strength or weakness on disposition. Skilled commanders shape the enemy, forcing them to follow. They offer bait the enemy must take, luring with benefits and striking with troops.

Skilled warriors seek victory through momentum, not demanding it from individuals, selecting the right people to harness momentum.

Those who wield momentum fight like rolling logs or stones—still when stable, moving when unstable, halting when square, rolling when round.

A skilled warrior’s momentum is like a round stone rolling down a thousand-foot mountain—this is energy.

Chapter 6: Weak Points and Strong**

Sun Tzu said:

Those who arrive first at the battlefield and await the enemy are rested; those who arrive late and rush to fight are weary.

Skilled warriors bring the enemy to them, not the reverse.**To make the enemy come willingly, offer benefits. To prevent their advance, create obstacles.

When the enemy is rested, tire them; when sated, starve them; when secure, unsettle them.

Strike where they must rush to defend; advance where they least expect.

March a thousand miles without fatigue by traveling through uncontested land.

Attack and conquer by targeting undefended positions. Defend impregnably by guarding what the enemy does not attack.

Skilled attackers leave the enemy unsure of what to defend; skilled defenders leave the enemy unsure of what to attack.

Subtle and invisible, they leave no trace; mysterious and silent, they control the enemy’s fate.

Advance irresistibly by striking their weaknesses; retreat uncatchably by moving too swiftly.

To force battle, attack what the enemy must save. To avoid battle, defend in a way that prevents engagement. Shape the enemy while remaining formless, concentrating your forces while dividing theirs.

When concentrated, you are one; when the enemy is divided into ten, you strike one with ten, outnumbering them.

Fight where the enemy least expects, preparing many defenses while engaging few.

Defending the front weakens the rear; defending the rear weakens the front; defending the left weakens the right; defending everywhere leaves all weak.

Weakness comes from preparing against others; strength from forcing others to prepare against you.

Knowing the place and time of battle allows a thousand-mile march to engage.

Without this knowledge, left cannot aid right, front cannot aid rear, and coordination fails over miles or even leagues. In my estimation, even a numerous army like Yue’s gains no advantage without this knowledge.

Thus, victory can be shaped. Even a numerous enemy can be rendered unable to fight.

Analyze to know their plans’ strengths and weaknesses. Probe to know their movements and positions.

Shape to know their terrain’s life-or-death points.

Test to know their strengths and deficiencies.

The ultimate in shaping an army is formlessness.

Formless, even the deepest spies cannot penetrate, and the wisest cannot scheme against it.

Victory shaped to the masses’ perception is unknowable to them. All see the form of victory, but none know how it was shaped.

Victories are not repeated; they adapt infinitely to circumstances.

Military disposition is like water: water avoids heights and flows downward; armies avoid strengths and strike weaknesses. Water flows according to terrain; armies win according to the enemy.

Armies have no fixed momentum, just as water has no fixed form. Adapting to the enemy for victory is divine.

The five elements have no constant dominance, the seasons no fixed order, days vary in length, and the moon waxes and wanes.

Chapter 7: Maneuvering**

Sun Tzu said:

In warfare, a general receives orders from the ruler, assembles the army, and faces the enemy. Nothing is harder than maneuvering for advantage.

The difficulty lies in turning the circuitous into the direct and adversity into advantage.

Take a roundabout path, lure with bait, and arrive before the enemy despite starting later—this is mastering maneuver.

Maneuvering brings both advantage and danger. Moving the entire army for gain risks falling behind; abandoning baggage to advance risks losing supplies.

Marching swiftly, day and night, doubling the pace, risks collapse:

• At a hundred miles, all three generals may be captured, with only the strongest arriving, the weak trailing; one in ten reaches the goal.
• At fifty miles, the vanguard general falters, half arrive.
• At thirty miles, two-thirds arrive.

Without baggage, provisions, or reserves, the army perishes.

Those ignorant of neighboring states’ intentions cannot form alliances. Those unaware of terrain—mountains, forests, defiles, or marshes—cannot march. Without local guides, terrain advantages are lost.

Warfare thrives on deception, moves for advantage, and adapts through division or unity.

Be swift as wind, steady as a forest, aggressive as fire, immovable as a mountain, elusive as shadow, and strike like thunder.

Plunder villages to divide forces, secure territory to hold it, and act decisively when advantageous. Those who master circuitous routes win—this is the law of maneuvering.

Military texts say: When voices cannot be heard, use gongs and drums; when sights are obscured, use banners and flags.

Gongs, drums, banners, and flags unify the army’s senses. When united, the brave cannot advance alone, nor the timid retreat alone—this is commanding masses.

In night battles, use many fires and drums; in daylight, use banners and flags to adapt the army’s senses.

The enemy’s morale can be sapped, their general’s resolve shaken. Morning brings high spirits, noon brings lethargy, and evening brings exhaustion.

Skilled generals avoid the enemy’s high spirits, striking when they are weary or retreating—this is mastering morale.

Use order against chaos, calm against clamor—this is mastering the mind.

Use proximity against distance, rest against fatigue, satiety against hunger—this is mastering strength.

Avoid orderly banners and formidable formations—this is mastering adaptability.

In warfare: Do not attack uphill, oppose troops backed by hills, pursue feigned retreats, attack elite troops, take bait, block retreating armies, leave gaps for surrounded enemies, and do not press desperate foes.

This is the method of maneuvering.

Chapter 8: Variation in Tactics

Sun Tzu said:

In warfare, a general receives orders, assembles the army, and adapts to circumstances: Do not camp in treacherous terrain, ally in crossroads, linger in isolated areas, scheme in surrounded areas, and fight in death grounds.

Some routes should not be taken, some armies not attacked, some cities not besieged, some grounds not contested, and some orders not followed.

A general who masters the nine variations of terrain understands warfare. One who knows terrain but not these variations cannot fully exploit it. A commander unaware of these tactics, even with terrain knowledge, cannot fully utilize troops.

Wise commanders weigh both advantage and disadvantage.

Consider advantage to ensure success; consider disadvantage to avert calamity.

Subdue rivals with threats, engage them with tasks, and hasten them with gain.

In warfare: Do not rely on the enemy not coming, but on your readiness. Do not rely on them not attacking, but on your impregnability.

Five dangers for a general:

1. Reckless bravery leads to death.
2. Excessive caution leads to capture.
3. Quick temper invites insult.
4. Obsessive honor invites disgrace.
5. Overconcern for the people invites trouble.These five are flaws in a general, disasters in warfare. The destruction of armies and death of generals stem from these—examine them carefully.

Chapter 9: The Army on the March

Sun Tzu said:

When positioning and observing the enemy:

• In mountains, camp in valleys, occupy high ground with sunlight, and avoid uphill battles.
• Near water, stay away from the edge; if the enemy crosses, strike when half have crossed, not at the water’s edge. For battle, occupy high ground away from currents.
• In marshes, move quickly, do not linger; if fighting, rely on water and grass, with trees at your back.
• In flat terrain, choose open ground, with high ground at your back, danger ahead, and safety behind.

These are the advantages of terrain, as used by the Yellow Emperor to defeat the Four Emperors.

Armies prefer high ground over low, sunlight over shade, and solid ground for health, ensuring victory without disease.

On hills or embankments, occupy the sunny side with high ground at your back—this is terrain’s aid.

When rain upstream causes flooding, wait for the water to settle before crossing.

Avoid terrain with gorges, wells, cages, nets, traps, or crevices—move away quickly.

Keep distant from such terrain, let the enemy approach it; face it, let the enemy have it at their back.

Near hazards, ponds, reeds, woods, or dense cover, search carefully for ambushes.

Signs to observe:

• Quiet enemies nearby rely on hazards.
• Distant enemies provoking battle want you to advance.
• Occupying open ground suggests advantage.
• Moving trees signal approach.
• Many obstacles in grass indicate deception.
• Rising birds reveal ambushes.
• Startled beasts indicate a surprise attack.
• High, sharp dust signals chariots; low, broad dust signals infantry; scattered dust signals woodcutting; sparse, moving dust signals camp setup.
• Humble words with increased preparations signal advance; aggressive words with strong advances signal retreat.
• Unprovoked peace offers suggest plots.
• Light chariots moving to the flanks signal formation.
• Frantic troop movements indicate a planned attack.
• Half advancing, half retreating signals a lure.
• Soldiers leaning on weapons indicate hunger.
• Water carriers drinking first indicate thirst.
• Ignoring clear gains indicates fatigue.
• Gathering birds signal an empty camp.
• Nighttime shouts indicate fear.
• Disorderly camps suggest an unsteady general.
• Moving banners signal chaos.
• Angry officers suggest exhaustion.
• Killing horses for food signals no provisions.
• Abandoned cooking pots signal desperation.
• Subdued, hesitant speech suggests lost morale.
• Frequent rewards indicate distress.
• Frequent punishments indicate trouble.
• Initial harshness followed by fear of troops shows poor leadership.
• Envoys offering apologies seek rest.

When an angry enemy approaches but delays engagement without retreating, observe carefully.

Armies do not benefit from sheer numbers, but from avoiding reckless advances, consolidating strength, assessing the enemy, and seizing opportunities.

Those who underestimate the enemy without preparation are captured.

Punishing troops before they are loyal breeds resentment and disobedience. Loyal troops without discipline are unusable.

Lead with civility, unify with discipline—this ensures success.

Consistent orders train obedient troops; inconsistent orders breed disobedience.

Consistent leadership aligns the army with the commander’s will.

Chapter 10: Terrain

Sun Tzu said:

Terrain includes accessible, entangling, stalemated, narrow, precipitous, and distant types.

• Accessible: Both sides can move freely. Occupy high, sunny ground with secure supply lines for advantage.
• Entangling: Easy to advance, hard to retreat. Attack if the enemy is unprepared; if prepared, retreat is difficult, making it disadvantageous.
• Stalemated: Neither side benefits from advancing. Avoid attacking even if lured; withdraw to draw the enemy out, then strike when half-advanced.
• Narrow: Occupy first and fully prepare. If the enemy occupies it, do not attack if fortified; attack if not.
• Precipitous: Occupy high, sunny ground first. If the enemy holds it, withdraw, do not attack.
• Distant: Equal forces make challenging risky and disadvantageous.

These six are the principles of terrain, a general’s critical responsibility—examine them carefully.

Armies face six calamities, not from nature but from a general’s errors:

1. Flight: Equal forces attacking tenfold stronger.
2. Laxity: Strong troops, weak officers.
3. Collapse: Strong officers, weak troops.
4. Ruin: Angry subordinates fight independently, ignoring the general’s ability.
5. Disorder: A weak, lenient general with unclear training and inconsistent troops.
6. Rout: Misjudging the enemy, pitting few against many, weak against strong, without elite vanguards.

These six are paths to defeat, a general’s critical responsibility—examine them carefully.

Terrain is the army’s aid. Assessing the enemy, securing victory, and evaluating hazards and distances are the way of a superior general.

Those who understand and use terrain win; those who do not, lose.

If victory is certain, fight even if the ruler forbids; if defeat is likely, avoid battle even if ordered.

A general advances without seeking fame, retreats without avoiding blame, prioritizes the people’s safety and the ruler’s benefit—a state’s treasure.

Treat troops like infants, and they follow you into deep valleys; treat them like beloved sons, and they die with you.

But overindulgence without command, affection without discipline, or chaos without control renders troops unusable, like spoiled children.

Knowing your troops can strike but not the enemy’s vulnerability wins half the time.

Knowing the enemy is vulnerable but not your troops’ readiness wins half the time.

Knowing both but not the terrain’s suitability wins half the time.

Skilled commanders act decisively, with inexhaustible strategies.

Thus: Know yourself and the enemy for consistent victory; know heaven and earth for complete victory.

Chapter 11: The Nine Situations

Sun Tzu said:

Warfare involves nine types of ground: dispersive, frontier, contested, open, crossroads, serious, difficult, surrounded, and desperate.

• Dispersive: Fighting on home territory.
• Frontier: Shallow penetration into enemy land.
• Contested: Ground advantageous to both sides.
• Open: Both sides can move freely.
• Crossroads: Connecting multiple states, where securing alliances is key.
• Serious: Deep penetration with many enemy cities behind.
• Difficult: Challenging terrain like mountains, forests, or marshes.
• Surrounded: Narrow entry, circuitous retreat, where a small enemy force can strike your larger one.
• Desperate: Swift battle ensures survival; delay brings death.

Thus: Avoid battle in dispersive ground, do not linger in frontier ground, do not attack in contested ground, maintain connections in open ground, secure alliances in crossroads ground, plunder in serious ground, advance in difficult ground, scheme in surrounded ground, and fight in desperate ground.

Skilled ancient commanders ensured the enemy’s forces were disconnected, their numbers unreliable, their ranks unable to rescue each other, and their troops scattered and disorganized.

Act when advantageous, halt when not.

If asked, “How to face a numerous, disciplined enemy?”

Answer: “Seize what they value, and they will comply.”

Warfare prioritizes speed, striking through unexpected routes at unprepared targets.

When campaigning: Deep penetration unites the army, preventing enemy dominance. Plunder fertile lands to feed the troops.

Care for the troops, conserve strength, and plan unpredictably.

Place troops in desperate situations where they fight fearlessly, stand firm, remain loyal, and battle without hesitation.

Thus, the army is vigilant without urging, achieves without demanding, unites without orders, and trusts without decrees. Banish superstitions and doubts, and they face death willingly.

Soldiers forgo wealth, not because they disdain riches, but from necessity; they risk life, not because they reject longevity, but from duty. On the day of battle, tears stain the faces of seated soldiers, and those lying down weep.**In desperate straits, they fight with the courage of heroes like Zhuan Zhu or Cao Gui.

Skilled commanders are like the “rate snake” of Mount Chang: strike its head, the tail responds; strike its tail, the head responds; strike its middle, both respond.

If asked, “Can troops be made like the rate snake?”

Answer: “Yes.” Even enemies like Wu and Yue, when in the same boat during a storm, aid each other like hands.

Tying horses or burying wheels is unreliable. Unifying courage through discipline and balancing strength and flexibility with terrain are the keys.

Skilled commanders lead as if guiding a single person, driven by necessity.

A general’s duty is calm precision and orderly governance. Blind the troops to plans, change strategies, and obscure movements to keep them unaware.

Shift camps, take circuitous routes, and make return impossible, like climbing a height and discarding the ladder.

Lead deep into enemy lands, trigger the critical moment, burn boats, and break cauldrons, driving troops like sheep, unaware of their destination.

Gather the army and place it in peril—this is the general’s task.

Understand the nine grounds’ variations, the advantages of flexibility, and human nature’s principles.

When campaigning: Deep penetration unifies, shallow penetration scatters. Leaving your state to fight abroad is isolated ground; open routes are crossroads; deep penetration is serious ground; shallow is frontier; narrow entries with strong defenses are surrounded; no escape is desperate.

Thus:

• In dispersive ground, unify resolve.
• In frontier ground, maintain cohesion.
• In contested ground, hasten to secure it.
• In open ground, strengthen defenses.
• In crossroads ground, solidify alliances.
• In serious ground, secure provisions.
• In difficult ground, press forward.
• In surrounded ground, block gaps.
• In desperate ground, show no retreat.

Troops’ nature: When surrounded, they resist; when desperate, they fight; when pressed, they obey.

Those unaware of neighboring states’ plans cannot ally with them. Those ignorant of terrain cannot march. Those without guides cannot exploit terrain.

Without mastering these, an army cannot dominate.

A dominant army prevents enemy unity and alliances, not by competing for allies but by imposing its will, capturing cities, and toppling states.

Offer unconventional rewards and issue extraordinary orders, commanding the army as one.

Assign tasks without revealing plans, promise gains without warning of risks.

Place troops in mortal danger to survive; trap them in death to live. In peril, they achieve victory or defeat.

In warfare, feign compliance with the enemy’s intent, concentrate forces on a single goal, and strike generals over a thousand miles—this is achieving success through skill.

On the day of action, seal passes, destroy tallies, block envoys, and deliberate decisively in the temple.

When the enemy opens a gap, seize it swiftly, targeting what they value, without fixed plans.

Adapt to the enemy to decide the battle.

Begin like a maiden, luring the enemy to open their gates; then strike like a fleeing hare, too swift to resist.

Chapter 12: The Attack by Fire**

Sun Tzu said:

There are five types of fire attack:

1. Burning personnel.
2. Burning stores.
3. Burning baggage.
4. Burning arsenals.
5. Burning supply lines.

Fire attacks require preparation and conditions, with materials ready and timing based on dry weather or favorable constellations (Ji, Bi, Yi, or Zhen, when winds rise).

Adapt to the five fire variations:

• If fire breaks out inside, respond from outside.
• If fire burns but the enemy remains calm, wait, do not attack.
• When the fire peaks, follow up if feasible; if not, halt.
• If fire is set outside, act without waiting for internal conditions, at the right time.
• Fire from upwind, not downwind. Winds persisting by day often stop at night.

Armies must master the five fire variations and adhere to their principles.

Fire aids attacks with clarity; water aids with strength. Water divides but does not seize.

Victory without consolidating gains is disastrous, termed “costly delay.”

Thus: Wise rulers plan carefully, skilled generals execute diligently. Move only for gain, act only for advantage, fight only in peril.

Rulers must not mobilize out of anger, nor generals fight out of resentment.

Act when advantageous, halt when not.

Anger can turn to joy, resentment to satisfaction, but a lost state cannot be restored, nor the dead revived.

Wise rulers are cautious, skilled generals vigilant—this is the way to secure the state and preserve the army.

Chapter 13: The Use of Spies

Sun Tzu said:

Mobilizing a hundred thousand troops over a thousand miles costs the people and state a thousand gold pieces daily, disrupts internal and external affairs, exhausts travelers, and idles seven hundred thousand households.

Years of stalemate for a single day’s victory, yet begrudging titles or gold to learn the enemy’s plans, is the height of inhumanity—not the mark of a true general, a ruler’s aide, or a master of victory.

Wise rulers and skilled generals triumph and surpass others through foreknowledge.

Foreknowledge is not gained from spirits, omens, or calculations but from people who know the enemy’s situation.

There are five types of spies: local, insider, double, doomed, and living.

When all five operate undetected, this is the “divine web,” a ruler’s treasure.

• Local spies: Use the enemy’s locals.
• Insider spies: Use their officials.
• Double spies: Use their spies against them.
• Doomed spies: Spread false information to deceive the enemy, sacrificing themselves.
• Living spies: Return with reports.

The army relies on spies; none are rewarded more generously or kept more secret.

Only the wise can employ spies, only the benevolent can direct them, and only the subtle can extract their full value.

Spies are used everywhere. If a spy’s plan leaks before execution, both spy and informant die.

To strike an army, besiege a city, or assassinate an individual, first learn the names of their generals, aides, guards, and staff—spies must uncover these.

Identify enemy spies sent to observe you, turn them with incentives, and use them as double agents.

Through double agents, local and insider spies are recruited.

Through double agents, doomed spies spread deception.

Through double agents, living spies report reliably.

Rulers must master the five spies, relying on double agents, and treat them generously.

The rise of Yin was due to Yi Zhi’s espionage in Xia; Zhou’s rise was due to Lü Ya’s in Yin.

Only wise rulers and skilled generals using the most intelligent spies achieve great success.

This is the essence of warfare, the army’s foundation for action.