shàng bīng fá móu 上兵伐谋
The Best Strategy in Warfare is to Foil the Enemy’s Strategy.
Foiling the enemy’s strategy is an important principle proposed by Sunzi(545?-470?BC). In his view, war is waged at different levels, all of which have a significant impact on the outcome. Armed attacks will do great damage to both sides, so they should be avoided if at all possible. Those who are good at leading armies should be able to use stratagems to eliminate the threat of enemy attack in advance or clear the obstacles to their own armed forces to achieve their strategic goals at minimal cost.
The best strategy in warfare is to foil the enemy’s strategy, the next to break up their alliances, still the next to strike at their troops, and the worst to attack their walled cities. Attacking walled cities must be avoided if at all possible. (The Art of War)