Having _converted spies_, getting hold of the enemy’s spies and using
them for our own purposes.
By means of heavy bribes and liberal promises detaching them
from the enemy’s service, and inducing them to carry back false
information as well as to spy in turn on their own countrymen.
Thus Tu Yu: 因厚賂重許反使爲我間也. On the other hand, 蕭世諴 Hsiao
Shih-hsien in defining the 反間 says that we pretend not to
have detected him, but contrive to let him carry away a false
impression of what is going on (敵使人來候我我佯不知而示以虛事).
Several of the commentators accept this as an alternative
definition; but that it is not what Sun Tzŭ meant is conclusively
proved by his subsequent remarks about treating the converted spy
generously (§ 21 _sqq._). Ho Shih notes three occasions on which
converted spies were used with conspicuous success: 1) by T‘ien
Tan in his defence of Chi-mo (see _supra_, p. 90); 2) by Chao Shê
on his march to O-yü (see p. 57); and by the wily 范雎 Fan Chü
in 260 B.C., when Lien P‘o was conducting a defensive campaign
against Ch‘in. The King of Chao strongly disapproved of Lien P‘o’s
cautious and dilatory methods, which had been unable to avert a
series of minor disasters, and therefore lent a ready ear to the
reports of his spies, who had secretly gone over to the enemy and
were already in Fan Chü’s pay. They said: “The only thing which
causes Ch‘in anxiety is lest 趙括 Chao Kua should be made general.
Lien P‘o they consider an easy opponent, who is sure to be
vanquished in the long run.” Now this Chao Kua was a son of the
famous Chao Shê. From his boyhood, he had been wholly engrossed
in the study of war and military matters, until at last he came
to believe that there was no commander in the whole Empire who
could stand against him. His father was much disquieted by this
overweening conceit, and the flippancy with which he spoke of such
a serious thing as war, and solemnly declared that if ever Kua was
appointed general, he would bring ruin on the armies of Chao. This
was the man who, in spite of earnest protests from his own mother
and the veteran statesman 藺相如 Lin Hsiang-ju, was now sent to
succeed Lien P‘o. Needless to say, he proved no match for the
redoubtable Po Ch‘i and the great military power of Ch‘in. He
fell into a trap by which his army was divided into two and his
communications cut; and after a desperate resistance lasting 46
days, during which the famished soldiers devoured one another, he
was himself killed by an arrow, and his whole force, amounting,
it is said, to 400,000 men, ruthlessly put to the sword. [See
歷代紀事年表, ch. 19, ff. 48–50].