Being unconquerable lies with yourself; being conquerable lies with your enemy.
The ultimate in disposing one's troops is to be without ascertainable shape. Then the most penetrating spies cannot pry in nor can the wise lay plans against you.
One mark of a great soldier is that he fight on his own terms or fights not at all.
When he pretends to flee, do not pursue.
Those who would wage war, should first eliminate all domestic enemies before proceeding to attack the external foe.
In war, practice dissimulation and you will succeed.