Waging War

War is expensive in a way that compounds, and the commander who forgets this loses even when he wins battles.

His central warning is against prolonged operations. "When you engage in actual fighting, if victory is long in coming, the men's weapons will grow dull and their ardour will be damped." Sieges exhaust strength; protracted campaigns drain the treasury; and when resources are spent and spirits are low, neighboring rulers will rise to take advantage of the exhaustion. "Thus, though we have heard of stupid haste in war, cleverness has never been seen associated with long delays." There is, he insists, no instance of a country having benefited from prolonged warfare.

The solution is to make the war pay for itself. The skillful general does not levy a second conscription, nor load his supply wagons more than twice. He brings war material from home but forages on the enemy, because "one cartload of the enemy's provisions is equivalent to twenty of one's own" — the cost of transport across hostile distance is so great that captured supply is worth many times homegrown supply.

Sun Tzu links morale to incentive with unusual directness. To rouse soldiers to fight, anger them; to make them see the advantage of beating the enemy, reward them with the spoils. In chariot fighting, the soldier who first takes ten or more chariots should be rewarded, the captured chariots turned to your own use, the prisoners treated kindly and absorbed into your forces. This is "using the conquered foe to augment one's own strength."

The closing principle is that the supreme aim is a quick, decisive result, not a long, costly campaign. "In war, then, let your great object be victory, not lengthy campaigns." The leader of armies, he says, is the arbiter of the people's fate, the man on whom it depends whether the nation shall be in peace or in peril. The civilian application is plain: the true cost of any prolonged effort is the silent drain on the resources and morale that sustain it, and the leader who controls expenditure and ends conflicts swiftly preserves the very strength that makes future victories possible.