The principle of winning by the enemy mainly embodies the flexibility of Sun Wu's war guidance, emphasizing flexible use of troops and changeable tactics. He believes that "water flows because of the ground, and soldiers win because of the enemy." Therefore, the soldiers have no constant potential, the water is impermanent, and they can win because of the change of the enemy, which is called God. "Therefore, he advocated that commanding operations must be" invincible, but infinite "; In the course of fighting, we should "practice decisive battle with the enemy", so as to "accomplish things skillfully". "Sun Wu believes that when applying the principle of" winning with the enemy ",the key is to give full play to the head coach's subjective initiative and adopt different strategies and tactics according to the objective situation of combat. Take different countermeasures against different enemies, that is, "lure them to benefit, take them in disorder, prepare for them, avoid them when they are strong, scratch them when they are angry, be arrogant when they are humble, be successful when they are near, and leave them when they are near." "According to the strength of the force comparison, different forms of combat are adopted. When the enemy forces are dominant, I take the form of defense; When our forces are superior, we will take the form of attack. (xingpian: "insufficient rules, more attacks"). According to the strength of the troops, different tactics are adopted. In "Planning and Attack", he clearly pointed out: "Surround with ten, attack with five, and play in doubles, so that the enemy can fight, escape with few, and cannot avoid it. "This shows that there are three different situations of strength, and three different tactics should be adopted. When our army has the advantage, we should adopt siege tactics; When comparing the strength of the enemy and ourselves, we should adopt the tactics of dispersing the enemy first and then breaking it; When our army is at a disadvantage, we should adopt the tactics of driving out the enemy without fighting.