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 when to fight and when not to fight.
Those who would wage war, should first eliminate all domestic enemies before proceeding to attack the external foe.
He will win who knows how to handle both superior and inferior forces.
Sweat more during peace: bleed less during war
Pretend to be weak, so your enemy may grow arrogant.