It is said that if you know your enemies and know yourself, you will not be imperiled in a hundred battles; if you do not know your enemies but do know yourself, you will win one and lose one; if you do not know your enemies nor yourself, you will be imperiled in every single battle.
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.
The military has no constant form, just as water has no constant shape - adapt as you face the enemy, without letting them know beforehand what you are going to do.
If I determine the enemy's disposition of forces while I have no perceptible form, I can concentrate my forces while the enemy is fragmented. The pinnacle of military deployment approaches the formless: if it is formless, then even the deepest spy cannot discern it nor the wise make plans against it.
One whose troops repeatedly congregate in small groups here and there, whispering together, has lost the masses. One who frequently grants rewards is in deep distress. One who frequently imposes punishments is in great difficulty. One who is at first excessively brutal and then fears the masses is the pinnacle of stupidity.
It is imperative to contest all factions for complete victory, so the army is not garrisoned and the profit can be total. This is the law of strategic siege.