用间篇第十三   THE USE OF SPIES　　

孙子曰：凡兴师十万，出征千里，百姓之费，公家之奉，日费千金。 内外骚动，怠於道路，不得操事者，七十万家。相守数年，以争一日 之胜，而爱爵禄百金，不知敌之情者，不仁之至也。非人之将也，非 主之佐也，非胜之主也。故明君贤将，所以动而胜人，成功出於众者 ，先知也。先知者，不可取於鬼神，不可象於事，不可验於度。必取 於人，知敌之情者也。

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 labour.

 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 honours and emoluments, is the height of inhumanity.

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

 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.

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

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

故用间有五：有因间，有内间，有反间，有死间，有生间。五间俱起 ，莫知其道，是谓神纪，人君之宝也。因间者，因其乡人而用之。内 间者，因其官人而用之。反间者，因其敌间而用之。死间者，为诳事 於外，令吾闻知之，而传於敌间也。生间者，反报也。

 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.

 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.

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

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

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

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.

Surviving spies, finally, are those who bring back news from the enemy's camp.

故三军之事，莫亲於间，赏莫厚於间，事莫密於间。非圣智不能用间 ，非仁义不能使间，非微妙不能得间之实。微哉！微哉！无所不用间 也。间事未发，而先闻者，间与所告者兼死。

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.

Spies cannot be usefully employed without a certain intuitive sagacity.

They cannot be properly managed without benevolence and straightforwardness.

Without subtle ingenuity of mind, one cannot make certain of the truth of their reports.

Be subtle! be subtle! and use your spies for every kind of business.

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.

凡军之所欲击，城之所欲攻，人之所欲杀，必先知其守将、左右、谒 者、门者、舍人之姓名，令吾间必索知之。

 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.

必索敌人之间来间我者，因而利之，导而舍之，故反间可得而用也。 因是而知之，故乡间、内间可得而使也﹔因是而知之，故死间为诳事 可使告敌﹔因是而知之，故生间可使如期。五间之事，君必知之，知 之必在於反间，故反间不可不厚也。

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.

It is through the information brought by the converted spy that we are able to acquire and employ local and inward spies.

It is owing to his information, again, that we can cause the doomed spy to carry false tidings to the enemy.

Lastly, it is by his information that the surviving spy can be used on appointed occasions.

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.

昔殷之兴也，伊挚在夏；周之兴也，吕牙在殷。故惟明君贤将能以上智为间者，必成大功。此兵之要，三军之所恃而动也。

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.

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.