There are roads which must not be followed, armies which must not be attacked, towns which must not be besieged, positions which must not be contested, and commands of the sovereign which must not be obeyed.

The skillful general does not rely on the enemy not coming, but relies on his own readiness. He does not rely on the enemy not attacking, but relies on his own impregnability.

Place the army in a position of certain death, and they will fight to live. Place them in a position where there is no escape, and they will stand their ground.