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.
If ignorant both of your enemy and yourself, you are certain to be in peril.
He who knows when he can fight and when he cannot, will be victorious.
There has never been a protracted war from which a country has benefited.
If you are far from the enemy, make him believe you are near.
He who is prudent and lies in wait for an enemy who is not, will be victorious.