know where to defend: against those skilful in defence, the enemy does not know where to attack.
Now the secrets of the art of offence are not to be easily apprehended, as a certain shape or noise can be understood, of the senses; but when these secrets are once learnt, the enemy is mastered.
We attack, and the enemy cannot resist, because we attack his weakly held positions; we retire, and the enemy cannot pursue, because we retire too quickly.
Again, when we are anxious to fight, but the enemy is serenely secure behind high walls and deep moats; we attack some such other place that he must certainly come out to relieve.
When we do not want to fight, we occupy an unfortified line; and prevent the enemy from attacking by keeping him in suspense.
By making feints, and causing the enemy to be uncertain as to our movements, we unite, whilst he must divide.
We become one body; the enemy being separated into ten parts. We attack the divided ten with the united one. We are many, the enemy is few, and in numbers there is strength.
The place selected for attack must be kept secret. If the enemy knows not where he will be attacked, he must prepare in every quarter, and so be weak at every point of attack.
If the enemy strengthens his front, he must weaken his rear; if he strengthens his right, his left
