Those who do not know the plans of competitors cannot prepare alliances. Those who do not know the lay of the land cannot maneuver their forces. Those who do not use local guides cannot take advantage of the ground.
The general who advances without coveting fame and retreats without fearing disgrace, whose only thought is to protect his country and do good service for his sovereign, is the jewel of the kingdom.
It is according to the shapes that I lay the plans for victory, but the multitude does not comprehend this. Although everyone can see the outward aspects, none understands the way in which I have created victory.
The natural formation of the country is the soldier's best ally; but a power of estimating the adversary, of controlling the forces of victory, and of shrewdly calculating difficulties, dangers and distances, constitutes the test of a great general.
When you know both yourself as well as your competition, you are never in danger. To know yourself and not others, gives you half a chance of winning. Knowing neither yourself or your competition puts you in a position to lose.
No ruler should put troops into the field merely to gratify his own spleen; no general should fight a battle simply out of pique. If it is to your advantage, make a forward move; if not, stay where you are. Anger may in time change to gladness; vexation may be succeeded by content. But a kingdom that has once been destroyed can never come again into being; nor can the dead ever be brought back to life.
Should one ask: 'how do I cope with a well-ordered enemy host about to attack me?' I reply: seize something he cherishes and he will conform to your desires.
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.
There are three ways in which a ruler can bring misfortune on his army: By commanding the army to advance or to retreat, being ignorant of the fact that it cannot obey. This is called hobbling the army. By attempting to govern an army in the same way as he administers a kingdom, being ignorant of the conditions which obtain in an army. This causes restlessness in the soldier's minds. By employing the officers of his army without discrimination, through ignorance of the military principle of adaptation to circumstances. This shakes the confidence of the soldiers.
If we do not wish to fight, we can prevent the enemy from engaging us even though the lines of our encampment be merely traced out on the ground. All we need to do is to throw something odd and unaccountable in his way.