Attack him where he is unprepared, appear where you are not expected.

The sovereign must have full knowledge of the activities of the five sorts of agents. This knowledge must come from the double agents, and therefore it is mandatory that they be treated with the utmost liberality.

You can ensure the success of your attacks if you only attack places that are undefended. You can ensure the safety of your defense if you only hold positions that cannot be attacked. Therefore, that general 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.

Correct your mistake as soon as you have found it.

Therefore a victorious army first wins and then seeks battle; a defeated army first battles and then seeks victory.

Engage people with what they expect; it is what they are able to discern and confirms their projections. It settles them into predictable patterns of response, occupying their minds while you wait for the extraordinary moment - that which they cannot anticipate.

The good fighter is able to secure himself against defeat, but cannot make certain of defeating the enemy.