Before assaults, spy out enemy officials’ identities. Turn captured enemy spies into double agents, the core of all intelligence work. They support other four spy types and deserve lavish rewards under royal supervision.
Spies gain the utmost trust and highest rewards with absolute secrecy. Only wise, humane and astute commanders can effectively deploy spies. Anyone leaking spy plans faces execution together with the spy.
Sun Tzu categorizes five spy types: native, internal, double, doomed and surviving spies. Deploying all five simultaneously hides intelligence operations perfectly, forming an invaluable secret strategy for rulers.
Large campaigns drain national wealth and disrupt civilians. Skimping on spy funds to ignore enemy intelligence is reckless. Reliable foreknowledge for victory comes from human scouts, not superstition or divination.
Victories without consolidation bring ruin. Rulers and generals must wage war only for tangible gains, never out of rage. Anger fades, but ruined states and lost lives cannot be recovered; prudence safeguards the nation and army.
Adjust tactics flexibly for five fire attacks. Strike from windward only when flames blaze fiercely. Fire devastates foes thoroughly, while water merely blocks their advance; commanders must master all fire attack rules.
Sun Tzu lists five fire attack targets: soldiers, provisions, carts, storehouses and troop formations. Prearrange fire tools and launch assaults on dry, windy days when the moon passes four specific constellations for favorable winds.
Block passes and cut enemy envoys before war, devise thorough court plans. Strike swiftly at enemy gaps and seize their vital assets. Stay quiet as a maiden to lull guards, then dash like a hare to catch foes unprepared.
Three military prerequisites are stressed: grasping rival plots, terrain and local guides. A dominant army relies on its own strength, uses special rewards, drives troops into deadly straits, feints compliance and concentrates forces to slay enemy generals far away.