When the leader is morally weak and his discipline not strict, when his instructions and guidance are not enlightened, when there are no consistent rules, neighboring rulers will take advantage of this.
If, however, you are indulgent, but unable to make your authority felt; kind-hearted, but unable to enforce your commands; and incapable, moreover, of quelling disorder: then your soldiers must be likened to spoilt children; they are useless for any practical purpose.
Those who excel in war first cultivate their own humanity and and maintain their laws and institutions. By these means they make their governments invincible.
The skillful tactician may be likened to the shuai-jan. Now the shuai-jan is a snake that is found in the Ch'ang mountains. Strike at its head, and you will be attacked by its tail; strike at its tail, and you will be attacked by its head; strike at its middle, and you will be attacked by head and tail both.