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.

It is a doctrine of war not to assume the enemy will not come, but rather to rely on one's readiness to meet him; not to presume that he will not attack, but rather to make one's self invincible.

We may distinguish six kinds of terrain, to wit: (1) Accessible ground; (2) entangling ground; (3) temporising ground; (4) narrow passes; (5) precipitous heights; (6) positions at a great distance from the enemy.

Know the enemy, know yourself; your victory will never be endangered. Know the ground, know the weather; your victory will then be total.

Ground which can be abandoned but is hard to re-occupy is called entangling.

If the mind is willing, the flesh could go on and on without many things.

Know the enemy and know yourself.