Know thy enemy and know thy self and you will win a hundred battles.

Being unconquerable lies with yourself; being conquerable lies with your enemy.

If I wish to engage, then the enemy, for all his high ramparts and deep moat, cannot avoid engagement; I attack that which he is obliged to rescue.

Without local guides, your enemy employs the land as a weapon against you.

Hence the saying: The enlightened ruler lays his plans well ahead; the good general cultivates his resources.

Unhappy is the fate of one who tries to win his battles and succeed in his attacks without cultivating the spirit of enterprise, for the result is waste of time and general stagnation.

Carefully compare the opposing army with your own, so that you may know where strength is superabundant and where it is deficient.