War is a matter of vital importance to the state.

Convince your enemy that he will gain very little by attacking you; this will diminish his enthusiasm

Ground which can be freely traversed by both sides is called accessible.

Against those skilled in attack, an enemy does not know where to defend; against the experts in defense, the enemy does not know where to attack.

He will win who knows how to handle both superior and inferior forces.

On dispersive ground, therefore, fight not. On facile ground, halt not. On contentious ground, attack not. On open ground, do not try to block the enemy's way. On the ground of intersecting highways, join hands with your allies. On serious ground, gather in plunder. In difficult ground, keep steadily on the march. On hemmed-in ground, resort to stratagem. On desperate ground, fight.

Be subtle! be subtle! and use your spies for every kind of business.