Plan for what is difficult while it is easy, do what is great while it is small.

Without subtle ingenuity of mind, one cannot make certain of the truth of their reports.

O divine art of subtlety and secrecy! Through you we learn to be invisible, through you inaudible and hence we can hold the enemy's fate in our hands.

Spies cannot be usefully employed without a certain intuitive sagacity; They cannot be properly managed without benevolence and straightforwardness; Without subtle ingenuity of mind, one cannot make certain of the truth of their reports; Be subtle! be subtle! and use your spies for every kind of warfare; If a secret piece of news is divulged by a spy before the time is ripe, he must be put to death together with the man to whom the secret was told.

In warfare, there are no constant conditions. He who can modify his tactics in relation to his opponent will succeed and win.

Military tactics are like unto water; for water in its natural course runs away from high places and hastens downwards... Water shapes its course according to the nature of the ground over which it flows; the soldier works out his victory in relation to the foe whom he is facing. Therefore, just as water retains no constant shape, so in warfare there are no constant conditions. He who can modify his tactics in relation to his opponent and thereby succeed in winning, may be called a heaven-born captain.

One defends when his strength is inadequate, he attacks when it is abundant.