The Art of War by Sun Tzu: Summary & Notes

Rating: 8/10

Available at: Amazon

Related: 33 Strategies of War, 48 Laws of Power


A timeless book about the strategy of war. Many of the core principles apply beyond war to business and life in general.

The only knock is that much of the strategy is specific to warfare, while more modern books like 33 Strategies of War have broader applicability to modern life.

That said, you will always find new wisdom each time you re-read this book.



  • There is legend that this little book was Napoleon's key to success and his secret weapon.
  • Always remember, since ancient times, it has been known that..."the true object of war is peace."

I - Laying Plans

  • The art of war is of vital importance to the state. It is a matter of life and death, a road either to safety or to ruin. Hence under no circumstances can it be neglected.
  • All warfare is based on deception. Hence, when able to attack, we must seem unable; when using our forces, we must seem inactive; when we are near, we must make the enemy believe we are far away; when far away, we must make him believe we are near.
  • Hold out baits to entice the enemy. Feign disorder, and crush him. If he is secure at all points, be prepared for him. If he is in superior strength, evade him. If your opponent is of choleric temper, seek to irritate him. Pretend to be weak, that he may grow arrogant. If he is taking his ease, give him no rest. If his forces are united, separate them. Attack him where he is unprepared, appear where you are not expected.
  • The general who wins a battle makes many calculations in his temple before the battle is fought. The general who loses a battle makes but few calculations beforehand.

II - Waging War

  • Thus, though we have heard of stupid haste in war, cleverness has never been seen associated with long delays.
  • In all history, there is no instance of a country having benefited from prolonged warfare.

III - The Sheathed Sword

  • To fight and conquer in all your battles is not supreme excellence; supreme excellence consists in breaking the enemy's resistance without fighting.
  • There are three ways in which a sovereign can bring misfortune upon his army:
  • By commanding the army to advance or retreat, being ignorant of the fact that it cannot obey.
  • By attempting to govern an army in the same way as he administers a kingdom, being ignorant of the conditions that obtain in an army.
  • By employing the officers of his army without discrimination, through ignorance of the military principle of adaptation to circumstances.

Thus we may know that there are five essentials for victory:

  • He will win who knows when to fight and when not to fight.
  • He will win who knows how to handle both superior and inferior forces.
  • He will win whose army is animated by the same spirit throughout all its ranks.
  • He will win who, prepared himself, waits to take the enemy unprepared.
  • He will win who has the military capacity and is not interfered with by the sovereign.

If you know the enemy and you 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.

IV - Tactics

  • To secure ourselves against defeat lies in our own hands, but the opportunity of defeating the enemy is provided by the enemy himself.
  • The general who is skilled in defense hides in the most secret recesses of the earth; he who is skilled in attack flashes forth from the topmost heights of heaven.
  • Hence the skillful fighter puts himself into a position that makes defeat impossible and does not miss the moment for defeating the enemy.

V - Energy

  • Fighting with a large army under your command is nowise different from fighting with a small one: it is merely a question of instituting signs and signals.
  • In all fighting, the direct method may be used for joining battle, but indirect methods will be needed in order to secure victory.
  • Therefore the good fighter will be terrible in his onset, and prompt in his decision.
  • Simulated disorder postulates perfect discipline; simulated fear postulates courage; simulated weakness postulates strength.

VI - Weak Points & Strong

  • Appear at points that the enemy must hasten to defend; march swiftly to places where you are not expected.
  • The general that is skillful in attack whose opponent does not know what to defend; and he is skillful in defense whose opponent does not know what to attack.
  • In making tactical dispositions, the highest pitch you can attain is to conceal them;
  • Military tactics are like unto water; for water in its natural course runs away from high places and hastens downward. So in war, the way is to avoid what is strong and to strike at what is weak.
  • Water shapes its course according to the nature of the ground over which it flows; the soldier works out his victory in relation to the foe whom he is facing.
  • Therefore, just as water retains no constant shape, so in warfare there are no constant conditions.
  • He who can modify his tactics in relation to his opponent, and thereby succeed in winning, may be called a heaven-born captain.

VII - Maneuvering

  • Without harmony in the state, no military expedition can be undertaken; without harmony in the army, no battle array can be formed.
  • An army without its baggage train is lost; without provisions it is lost; without bases of supply it is lost.
  • Ponder and deliberate before you make a move. He will conquer who has learned the artifice of deviation. Such is the art of maneuvering.
  • In battle, a courageous spirit is everything.
  • A clever general, therefore, avoids and army when its spirit is keen, but attacks it when it is sluggish and inclined to return.
  • When you surround an enemy, leave an outlet free. This does not mean that the enemy is to be allowed to escape. The object is to make him believe that there is a road to safety, and thus prevent his fighting with the courage of despair.

VIII - Variation of Tactics

  • No town should be attacked which, if taken, cannot be held, or if left alone, will not cause any trouble.
  • In the wise leader's plans, considerations of advantage and of disadvantage will be blended together.
  • The art of war teaches us to rely not on the likelihood of the enemy's not coming, but on our own readiness to receive him; not on the chance of his not attacking, but rather on the fact that we have made our position unassailable.
  • There are five dangerous faults that may affect a general, of which the first two are: recklessness, which leads to destruction; and cowardice, which leads to capture.
  • Next there is a delicacy of honor, which is sensitive to shame; and a hasty temper, which can be provoked by insults.
  • The last of such faults is oversolicitude for his men, which exposes him to worry and trouble, for in the long run the troops will suffer more from the defeat, or at best, the prolongation fo the war, which will be the consequence.

IX - The Army on the March

  • He who exercises no forethought but makes light of his opponents is sure to be captured by them.
  • Humble words and increased preparations are signs that the enemy is about to advance. Violent language and driving forward as if to the attack are signs that he will retreat.
  • Peace proposals unaccompanied by a sworn covenant indicate a plot.
  • To begin by bluster, but afterward to take fright at the enemy's numbers, shows a supreme lack of intelligence.

X - Terrain

  • Sometimes an army is exposed to calamities, not arising from natural causes, but from faults for which the general is responsible. These are: flight; insubordination; collapse; ruin; disorganization; rout.
  • Regard your soldiers as your children, and they will follow you into the deepest valleys; look on them as your own beloved sons, and they will stand by you even unto death.
  • If we know that our own men are in a condition to attack, but are unaware that the enemy is not open to attack, we have gone only halfway toward victory. If we know that the enemy is open to attack, but are unaware that our own men are not in a condition to attack, we have gone only halfway toward victory. If we know that the enemy is open to attack, and also know that our men are in a condition to attack, but are unaware that the nature of the ground makes fighting impracticable, we have still gone only halfway toward victory.
  • If you know the enemy and you know yourself, your victory will not stand in doubt;

XI - The Nine Situations

  • Rapidity is the essence of war. Take advantage of the enemy's unreadiness, make your way by unexpected routes, and attack unguarded spots.
  • Carefully study the well-being of your men, and do not overtax them.
  • Concentrate your energy and hoard your strength.
  • Keep your army continually on the move, and devise unfathomable plans.
  • You will not succeed unless your men have tenacity and unity of purpose, and above all, a spirit of sympathetic cooperation.
  • By altering his arrangements and changing his plans, the skillful general keeps the enemy without definite knowledge.
  • By shifting his camp and taking circuitous routes, he prevents the enemy from anticipating his purpose.
  • Success in warfare is gained by carefully accommodating ourselves to the enemy's purpose. If the enemy shows an inclination to advance, lure him on to do so; if he is anxious to retreat, delay on purpose that he may carry out his intention.

XII - Attack by Fire

  • Move not unless you see an advantage; use not your troops unless there is something to be gained; fight not unless the position is critical.

XIII - The Use of Spies

  • What enables the wise sovereign and the good general to strike and conquer, and achieve things beyond the reach of ordinary men, is foreknowledge.
  • Having converted spies means getting hold of the enemy's spies and using them for our own purposes: by means of heavy bribes and liberal promises, detaching them from the enemy's service and inducing them to carry back false information as well as to spy in turn on their own countrymen.
  • There must be no more intimate relations in the whole army than those maintained by spies. No other relation should be more liberally rewarded. In no other relation should greater secrecy be preserved.
  • Whether the object be to crush an army, to storm a city, or to assassinate an individual, it is always necessary to begin by finding out the names of the attendants, the aides-de-camp, the doorkeepers, and the sentries of the general in command. Our spies must be commissioned to ascertain these.
  • The end and aim of spying in all its five varieties is knowledge of the enemy; and this knowledge can only be derived, in the first instance, from the converted spy. He not only brings information himself, but makes it possible to use the other kinds of spies to advantage. Hence it is essential that the converted spy be treated with the utmost liberality.
  • Spies are a most important element in war, because upon them depends an army's ability to move.

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