You can prevent your opponent from defeating you through defense, but you cannot defeat him without taking the offensive.

Those skilled in attack move as from above the nine-fold heavens. Thus they are capable both of protecting themselves and of gaining complete victory.

When you do battle, even if you are winning, if you continue for a long time it will dull your forces and blunt you edge...If you keep your armies out in the field for a long time, your supplies will be insufficient. Transportation of provisions itself consumes 20 times the amount transported.

The proximity of an army causes prices to go up; and high prices cause people's substance to be drained away. When their substance is drained away, they will be afflicted by heavy exactions. With this loss of substance and exhaustion of strength, the homes of the people will be stripped bare, and their incomes dissipated.

Agitate him and ascertain the pattern of his movement.

Hiding order beneath the cloak of disorder is simply a question of subdivision; concealing courage under a show of timidity presupposes a fund of latent energy; masking strength with weakness is to be effected by tactical dispositions.

The opportunity of defeating the enemy is provided by the enemy himself.