作战
War is ruinously expensive, so speed beats perfection: win quickly, never drag a campaign out, and live off the enemy's supplies to spare your own.
What this chapter says
Sun Tzu turns to cost. A large army in the field devours the treasury daily — provisions, transport, and equipment ruin the state long before the enemy does. A protracted war blunts weapons, dampens morale, exhausts strength, and tempts other powers to strike while you are spent. Therefore what matters is a swift victory, not a clever, drawn-out one: 'though we have heard of stupid haste in war, cleverness has never been seen associated with long delays.' The wise general also feeds his army from captured supplies rather than shipping everything from home, because one cartload taken from the enemy is worth twenty of one's own. Economy and speed, not endurance, decide who can afford to win.
Key lines
Applied today
Prolonged, cash-burning campaigns — price wars, endless roadmaps — exhaust you and invite disruption while you're spent. A decisive, faster win usually beats a drawn-out pursuit of the 'perfect' one.
Sustained conflict is costly for everyone involved, and bystanders may exploit both sides' exhaustion. Where you can, resolve a dispute quickly rather than letting it grind on out of pride.