Chapter 13: The Use of Spies
From Sun Tzu’s The Art of War (Lionel Giles translation, 1910).
The closing chapter on intelligence. Sun Tzu says victory depends on foreknowledge, and foreknowledge comes from spies — not from omens. He names five classes of agent and demands they be trusted and rewarded.
Key principles
- Foreknowledge wins; it cannot come from superstition or guesswork.
- Use five kinds of agents: native, inward, converted, doomed, and surviving.
- Reward spies well and keep their work secret.
Quotations from this chapter
Drawn from our sourced lesson database — each links to its permanent page with the full interpretation.
“Raising a host of a hundred thousand men and marching them great distances entails heavy loss and a drain on the resources of the State.”
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“To remain in ignorance of the enemy's condition simply because one grudges the outlay of a hundred ounces of silver is the height of inhumanity.”
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“What enables the wise sovereign and the good general to strike and conquer is foreknowledge.”
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“This foreknowledge cannot be elicited from spirits; it cannot be obtained inductively from experience, nor by deductive calculation.”
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“There are five classes of spies: local, inward, converted, doomed, and surviving spies.”
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Modern applications
- Pay for real market intelligence instead of trusting hunches.
- Build trusted inside sources; protect them and compensate them fairly.
Related strategy topics
Sun Tzu on RiskSun Tzu for BusinessSun Tzu on Decision-MakingSun Tzu on CompetitionSun Tzu on NegotiationSun Tzu on Leadership
Frequently asked questions
Why does The Art of War end with spies?
Because Sun Tzu treats victory as a product of foreknowledge. The final chapter argues you cannot win without knowing the enemy’s true state, and that knowledge must be earned through reliable intelligence, not omens.