Chapter 5
In general, the essentials of warfare are these: when one’s forces are few, one must be solid; when they are many, one must be orderly. Few troops are suited to shifting tactics; many troops are suited to open, direct confrontation. With many troops, the key is to advance and halt in good order; with few troops, the key is flexibility in advance and retreat. When our large army deals with a small enemy force, surround it from a distance and deliberately leave a gap. If our forces are few, attack in relays and waves to deal with the enemy’s large army. If the enemy is thrown into confusion by our actions, seize the opportunity and adapt as circumstances require. When we hold favorable ground, furl the banners, lure the enemy in, and then strike back at them. If the enemy is numerous, concentrate our troops and prepare to withstand encirclement. If the enemy is few and fearful, leave a gap and give them a way out; do not slaughter them to the last man.
In warfare, one should have the wind at one’s back, high ground behind one, high ground on the right, and strategic terrain on the left. Low-lying marshes and ground liable to collapse must all be avoided. Choose ground that is high on all sides and low in the middle, like a turtle shell, and encamp there.
In warfare, after deploying the formation, observe the enemy’s movements, and act only after clearly assessing the situation. If the enemy holds still, we quietly confront them, do not beat the drums to attack, and wait for the enemy to move first. When intending to attack, concentrate our forces and wait for the right moment.
In warfare, vary the size of one’s forces to test the enemy’s reaction; advance and retire to test whether the enemy’s formation is firm; create a critical situation to see whether the enemy is afraid; remain quiet to observe whether the enemy is slack; make feints to see whether the enemy is confused; launch a sudden attack to test whether the enemy’s ranks are orderly. Attack when the enemy hesitates; strike when the enemy is hurried; force the enemy onto the defensive; disrupt the enemy’s original deployment. Seize the moment when the enemy rashly advances; block the enemy’s plans; throw the enemy’s schemes into disorder; strike when the enemy is afraid.
In pursuing a fleeing enemy, do not halt to rest. If the enemy halts on the way, be on guard. Whenever you press close to an enemy capital, your advance must leave open a route forward, and your retreat must have a prearranged route back.
In warfare, striking too early easily exhausts one’s troops; acting too late easily breeds fear. Halting to rest causes slackness; fighting without pause causes exhaustion; resting too long instead produces reluctance to fight.
Cut off the enemy’s letters home and sever their contact with kin—this removes the enemy soldiers’ concern for those behind them. Select the elite and marshal weapons—this strengthens one’s own fighting power. Discard excess baggage and reduce ration loads, so that soldiers resolve to fight to the death. These are methods of governing an army handed down from antiquity.