rd move;
if not, stay where you are.

20. Anger may in time change to gladness; vexation may
be succeeded by content.

21. But a kingdom that has once been destroyed can
never come again into being; nor can the dead ever
be brought back to life.

22. Hence the enlightened ruler is heedful,
and the good general full of caution. This is the way
to keep a country at peace and an army intact.

XIII. THE USE OF SPIES

1. Sun Tzu said: Raising a host of a hundred thousand
men and marching them great distances entails heavy loss
on the people and a drain on the resources of the State.
The daily expenditure will amount to a thousand ounces
of silver. There will be commotion at home and abroad,
and men will drop down exhausted on the highways.
As many as seven hundred thousand families will be impeded
in their labor.

2. Hostile armies may face each other for years,
striving for the victory which is decided in a single day.
This being so, to remain in ignorance of the enemy's
condition simply because one grudges the outlay of a hundred
ounces of silver in honors and emoluments, is the height
of inhumanity.

3. One who acts thus is no leader of men, no present
help to his sovereign, no master of victory.

4. Thus, what enables the wise sovereign and the good
general to strike and conquer, and achieve things beyond
the reach of ordinary men, is foreknowledge.

5. Now this foreknowledge cannot be elicited from spirits;
it cannot be obtained inductively from experience,
nor by any deductive calculation.

6. Knowledge of the enemy's dispositions can only
be obtained from other men.

7. Hence the use of spies, of whom there are five classes:
(1) Local spies; (2) inward spies; (3) converted spies;
(4) doomed spies; (5) surviving spies.

8. When these five kinds of spy are all at work,
none can discover the secret system. This is called "divine
manipulation of the threads." It is the sovereign's
most precious faculty.

9. Having local spies means employing the services
of the inhabitants of a district.

10. Having inward spies, making use of officials
of the enemy.

11. Having converted spies, getting hold of the enemy's
spies and using them for our own purposes.

12. Having doomed spies, doing certain things openly
for purposes of deception, and allowing ou