A leader leads by example not by force.

He who wishes to fight must first count the cost

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.

These are the six ways of courting defeat - neglect to estimate the enemy's strength; want of authority; defective training; unjustifiable anger; nonobservance of discipline; failure to use picked men.

In warfare, there are no constant conditions. He who can modify his tactics in relation to his opponent will succeed and win.

Hence that general is skilful in attack whose opponent does not know what to defend; and he is skilful in defense whose opponent does not know what to attack.

Agitate him and ascertain the pattern of his movement.