“When you surround an army, leave an outlet free. Do not press a desperate foe too hard.”
A trapped foe fights hardest; leave an exit and he chooses flight over frenzy.
Chapter 7’s most merciful-looking maxim is pure mechanics: when you surround an army, leave an outlet free; do not press a desperate foe too hard. Sun Tzu’s reasoning is not compassion but force accounting — a cornered enemy stops calculating survival and fights at maximum cost per inch. The visible exit converts fight into flight, and flight into the cheap victory of occupation.
A company executes a flawless talent raid on a failing rival — then publicly celebrates each hire and predicts the rival’s collapse. The remaining forty engineers, now with nothing to lose and an audience, ship in six months the product rebuild that saves their employer. The raider’s own recruiters note the pattern: after each "victory," the surviving rival fights harder. The outlet unpressed is called grace in most traditions; in Chapter 7 it is called leaving the door to victory open.
The outlet must be real, not theater — a fake escape route is discovered, and betrayed corners fight worse than honest ones. And the rule scales down cleanly: negotiations, disputes, pricing wars all have their cornered moments. The question is never whether you can press; it is whether pressing past the breakpoint buys the victory or just a costlier version of it.