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 our spies to know of them and

report them to the enemy.

13. Surviving spies, finally, are those who

bring back news from the enemy's camp.

14. Hence it is that which none in the

whole army are more intimate relations to

be maintained than with spies.

None should be more liberally rewarded.

In no other business should greater secrecy

be preserved.

15. Spies cannot be usefully employed

without a certain intuitive sagacity.

16. They cannot be properly managed without

benevolence and straightforwardness.

17. Without subtle ingenuity of mind, one

cannot make certain of the truth of their

reports.

18. Be subtle! Be subtle! and use your

spies for every kind of business.

19. If a secret piece of news is divulged

by a spy before the time is ripe, he must

be put to death together with the man to

whom the secret was told.

20. Whether the object be to crush an army,

to storm a city, or to assassinate an

individual, it is always necessary to begin

by finding out the names of the attendants,

the aides-de-camp, and door-keepers and

sentries of the general in command.

Our spies must be commissioned to ascertain

these.

21. The enemy's spies who have come to spy

on us must be sought out, tempted with

bribes, led away and comfortably housed.

Thus they will become converted spies and

available for our service.

22. It is through the information brought

by the converted spy that we are able to

acquire and employ local and inward spies.

23. It is owing to his information, again,

that we can cause the doomed spy to carry

false tidings to the enemy.

24. Lastly, it is by his information that

the surviving spy can be used on appointed

occasions.

25. The end and aim of spying in all its

five varieties is knowledge of the enemy;

and this knowledge can only be derived, in

the first instance, from the converted spy.

Hence it is essential that the converted

spy be treated with the utmost liberality.

26. Of old, the rise of the Yin dynasty was

due to I Chih who had served under the

Hsia.

Likewise, the rise of the Chou dynasty was

due to Lu Ya who had served under the Yin.

27. Hence it is only the enlightened ruler

and the wise general who will use the

highest intelligence of the army for

purposes of spying and thereby they achieve

great results.

Spies are a most important element in

water, because on them depends an army's

ability to move.