In desperate position, you must fight.

To ... not prepare is the greatest of crimes; to be prepared beforehand for any contingency is the greatest of virtues.

Great results, can be achieved with small forces.

Ultimate excellence lies not in winning every battle, but in defeating the enemy without ever fighting.

Hence the saying: If you know the enemy and you know yourself, your victory will not stand in doubt; if you now Heaven and you know Earth, you may make your victory complete.

Attack the enemy's strategy.

If you are far from the enemy, make him believe you are near.