Agitate him and ascertain the pattern of his movement.

There is nothing more difficult than tactical maneuvering. The difficult consists in turning the devious into the direct, and misfortune into gain. Thus, to take a long and circuitous route after enticing the enemy out of the way, and though starting after him to contrive to reach the goal before him, shows knowledge of the artifice of deviation.

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.

Who can determine where one ends and the other begins?

When the thunderclap comes, there is no time to cover the ears.

If not in the interests of the state, do not act. If you cannot succeed, do not use troops. If you are not in danger, do not fight.

War is a matter of vital importance to the state.