Generally, the principles of warfare are:
The general receives his commands from the ruler, assembles the troops, mobilizes the army, and sets up camp.
There is nothing more difficult than armed struggle. In armed struggle, the difficulty is turning the circuitous into the direct, and turning adversity into advantage. Therefore, if you make the enemy’s route circuitous and bait him with advantages, though you start out behind him, you will arrive before him.
This is to know the calculations of the circuitous and of the direct. Therefore, armed struggle has advantages, and armed struggle has risks.
If the entire army mobilizes for an advantage, you will not arrive on time. If a reduced army mobilizes for an advantage, your stores and equipment will be lost. For this reason, by rolling up your armor, rushing forward without stopping day or night, covering twice the usual distance for an advantage a hundred li away, the general will be captured.
The strong will arrive first, the weak will lag behind, and as a rule, only one-tenth will arrive. If one struggles for an advantage fifty li away, the general of the front forces will be thwarted, and as a rule only one half will arrive.
If one struggles for an advantage thirty li away, then two-thirds of the army will arrive. For this reason, if an army is without its equipment it will lose; if an army is without its provisions it will lose; if the army is without its stores it will lose.
Therefore, one who does not know the intentions of the rulers of the neighboring states cannot secure alliances.
One who does not know the mountains and forests, gorges and defiles, swamps and wetlands cannot advance the army. One who does not use local guides cannot take advantage of the ground.
Therefore, the army is established on deception, mobilized by advantage, and changed through dividing up and consolidating the troops.
Therefore, it advances like the wind; it marches like the forest; it invades and plunders like fire; it stands like the mountain; it is formless like the dark; it strikes like thunder.
When you plunder the countryside, divide the wealth among your troops; when you expand your territory, divide up and hold places of advantage.
Calculate the situation, and then move. Those who know the principles of the circuitous and direct will be victorious.
This is armed struggle.
The Book of Military Administration says:
It is because words cannot be clearly heard in battle, drums and gongs are used; it is because troops cannot see each other clearly in battle, flags and pennants are used.
Therefore, in night battles use torches and drums; in day battles use flags and pennants. Drums, gongs, flags, and pennants are used to unite men’s eyes and ears. When the men are united, the brave cannot advance alone, the cowardly cannot retreat alone. These are the principles for employing a large number of troops.
Therefore, in night battles, use many torches and drums, and in day battles, use many flags and pennants in order to influence men’s eyes and ears.
The energy of the army can be dampened, and the general’s mind can be dampened. Therefore, in the morning, energy is high, but during the day energy begins to flag; and in the evening, energy is exhausted. Therefore, those skilled in the use of force avoid high energy, and strike when energy is exhausted.
This is the way to manage energy.
Disciplined, wait for disorder; calm, wait for clamor.
This is the way to manage the mind.
Near, wait for the distant; rested, wait for the fatigued; full, wait for the hungry.
This is the way to manage strength.
Do not do battle with well-ordered flags; do not do battle with well-regulated formations.
This is the way to manage adaptation.
Therefore, the principles of warfare are:
- Do not attack an enemy that has the high ground;
- Do not attack an enemy that has his back to a hill;
- Do not pursue feigned retreats;
- Do not attack elite troops;
- Do not swallow the enemy’s bait;
- Do not thwart an enemy retreating home.
- If you surround the enemy, leave an outlet;
- Do not press an enemy that is cornered.
These are the principles of warfare.