The Art of War - 12

Ch’i, being subsequently attacked without warning by Han Hsin, and
infuriated by what he considered the treachery of Li I-chi, ordered the
unfortunate envoy to be boiled alive.]

13. _Surviving spies_, finally, are those who bring back news from the
enemy’s camp.
[This is the ordinary class of spies, properly so called, forming a
regular part of the army. Tu Mu says: "Your surviving spy must be a man
of keen intellect, though in outward appearance a fool; of shabby
exterior, but with a will of iron. He must be active, robust, endowed
with physical strength and courage; thoroughly accustomed to all sorts
of dirty work, able to endure hunger and cold, and to put up with shame
and ignominy." Ho Shih tells the following story of Ta’hsi Wu of the
Sui dynasty: "When he was governor of Eastern Ch’in, Shen-wu of Ch’i
made a hostile movement upon Sha-yuan. The Emperor T’ai Tsu [? Kao Tsu]
sent Ta-hsi Wu to spy upon the enemy. He was accompanied by two other
men. All three were on horseback and wore the enemy’s uniform. When it
was dark, they dismounted a few hundred feet away from the enemy’s camp
and stealthily crept up to listen, until they succeeded in catching the
passwords used in the army. Then they got on their horses again and
boldly passed through the camp under the guise of night-watchmen; and
more than once, happening to come across a soldier who was committing
some breach of discipline, they actually stopped to give the culprit a
sound cudgeling! Thus they managed to return with the fullest possible
information about the enemy’s dispositions, and received warm
commendation from the Emperor, who in consequence of their report was
able to inflict a severe defeat on his adversary."]

14. Hence it is that with none in the whole army are more intimate
relations to be maintained than with spies.
[Tu Mu and Mei Yao-ch’en point out that the spy is privileged to enter
even the general’s private sleeping-tent.]

None should be more liberally rewarded. In no other business should
greater secrecy be preserved.
[Tu Mu gives a graphic touch: all communication with spies should be
carried "mouth-to-ear." The following remarks on spies may be quoted
from Turenne, who made perhaps larger use of them than any previous
commander: "Spies are attached to those who give them most, he who pays
them ill is never served. They should never be known to anybody; nor
should they know one another. When they propose anything very material,
secure their persons, or have in your possession their wives and
children as hostages for their fidelity. Never communicate anything to
them but what is absolutely necessary that they should know. [2] ]

15. Spies cannot be usefully employed without a certain intuitive
[Mei Yao-ch’en says: "In order to use them, one must know fact from
falsehood, and be able to discriminate between honesty and
double-dealing." Wang Hsi in a different interpretation thinks more
along the lines of "intuitive perception" and "practical intelligence."
Tu Mu strangely refers these attributes to the spies themselves:
"Before using spies we must assure ourselves as to their integrity of
character and the extent of their experience and skill." But he
continues: "A brazen face and a crafty disposition are more dangerous
than mountains or rivers; it takes a man of genius to penetrate such."
So that we are left in some doubt as to his real opinion on the

16. They cannot be properly managed without benevolence and
[Chang Yu says: "When you have attracted them by substantial offers,
you must treat them with absolute sincerity; then they will work for
you with all their might."]

17. Without subtle ingenuity of mind, one cannot make certain of the
truth of their reports.
[Mei Yao-ch’en says: "Be on your guard against the possibility of spies
going over to the service of the enemy."]

18. Be subtle! be subtle! and use your spies for every kind of
[Cf. VI. § 9.]

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.
[Word for word, the translation here is: "If spy matters are heard
before [our plans] are carried out," etc. Sun Tzŭ’s main point in this
passage is: Whereas you kill the spy himself "as a punishment for
letting out the secret," the object of killing the other man is only,
as Ch’en Hao puts it, "to stop his mouth" and prevent news leaking any
further. If it had already been repeated to others, this object would
not be gained. Either way, Sun Tzŭ lays himself open to the charge of
inhumanity, though Tu Mu tries to defend him by saying that the man
deserves to be put to death, for the spy would certainly not have told
the secret unless the other had been at pains to worm it out of him."]

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,
[Literally "visitors", is equivalent, as Tu Yu says, to "those whose
duty it is to keep the general supplied with information," which
naturally necessitates frequent interviews with him.]

the door-keepers and sentries of the general in command. Our spies must
be commissioned to ascertain these.
[As the first step, no doubt towards finding out if any of these
important functionaries can be won over by bribery.]

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.
[Tu Yu says: "through conversion of the enemy’s spies we learn the
enemy’s condition." And Chang Yu says: "We must tempt the converted spy
into our service, because it is he that knows which of the local
inhabitants are greedy of gain, and which of the officials are open to

23. It is owing to his information, again, that we can cause the doomed
spy to carry false tidings to the enemy.
[Chang Yu says, "because the converted spy knows how the enemy can best
be deceived."]

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.
[As explained in §§ 22-24. He not only brings information himself, but
makes it possible to use the other kinds of spy to advantage.]

Hence it is essential that the converted spy be treated with the utmost
26. Of old, the rise of the Yin dynasty
[Sun Tzŭ means the Shang dynasty, founded in 1766 B.C. Its name was
changed to Yin by P’an Keng in 1401.

was due to I Chih
[Better known as I Yin, the famous general and statesman who took part
in Ch’eng T’ang’s campaign against Chieh Kuei.]

who had served under the Hsia. Likewise, the rise of the Chou dynasty
was due to Lü Ya
[Lu Shang rose to high office under the tyrant Chou Hsin, whom he
afterwards helped to overthrow. Popularly known as T’ai Kung, a title
bestowed on him by Wen Wang, he is said to have composed a treatise on
war, erroneously identified with the _Liu T’ao_.]

who had served under the Yin.
[There is less precision in the Chinese than I have thought it well to
introduce into my translation, and the commentaries on the passage are
by no means explicit. But, having regard to the context, we can hardly
doubt that Sun Tzŭ is holding up I Chih and Lu Ya as illustrious
examples of the converted spy, or something closely analogous. His
suggestion is, that the Hsia and Yin dynasties were upset owing to the
intimate knowledge of their weaknesses and shortcoming which these
former ministers were able to impart to the other side. Mei Yao-ch’en
appears to resent any such aspersion on these historic names: "I Yin
and Lu Ya," he says, "were not rebels against the Government. Hsia
could not employ the former, hence Yin employed him. Yin could not
employ the latter, hence Hou employed him. Their great achievements
were all for the good of the people." Ho Shih is also indignant: "How
should two divinely inspired men such as I and Lu have acted as common
spies? Sun Tzŭ’s mention of them simply means that the proper use of
the five classes of spies is a matter which requires men of the highest
mental caliber like I and Lu, whose wisdom and capacity qualified them
for the task. The above words only emphasize this point." Ho Shih
believes then that the two heroes are mentioned on account of their
supposed skill in the use of spies. But this is very weak.]

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.
[Tu Mu closes with a note of warning: "Just as water, which carries a
boat from bank to bank, may also be the means of sinking it, so
reliance on spies, while production of great results, is oft-times the
cause of utter destruction."]

Spies are a most important element in war, because on them depends an
army’s ability to move.
[Chia Lin says that an army without spies is like a man with ears or

[1] "Aids to Scouting," p. 2.
[2] "Marshal Turenne," p. 311.