ATTACK BY STRATAGEM

 1. Sun Tzu said: In the practical art of war, the best
  thing of all is to take the enemy's country whole and intact;
  to shatter and destroy it is not so good. So, too, it is
  better to recapture an army entire than to destroy it,
  to capture a regiment, a detachment or a company entire
  than to destroy them.

 2. Hence to fight and conquer in all your battles
  is not supreme excellence; supreme excellence consists
  in breaking the enemy's resistance without fighting.

 3. Thus the highest form of generalship is to
  balk the enemy's plans; the next best is to prevent
  the junction of the enemy's forces; the next in
  order is to attack the enemy's army in the field;
  and the worst policy of all is to besiege walled cities.

 4. The rule is, not to besiege walled cities if it
  can possibly be avoided. The preparation of mantlets,
  movable shelters, and various implements of war, will take
  up three whole months; and the piling up of mounds over
  against the walls will take three months more.