Know thy enemy and know thy self and you will win a hundred battles.
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.
In the midst of chaos, there is also opportunity.
The control of a large force is the same principle as the control of a few men: it is merely a question of dividing up their numbers.
Ponder and deliberate before you make a move.
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.