[Mei Yao-ch`en has rather an interesting note: "Knowledge of the spirit-world is to be obtained by divination; information in natural science may be sought by inductive reasoning; the laws of the universe can be verified by mathematical calculation: but the dispositions of an enemy are ascertainable through spies and spies alone."]
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.
[Cromwell, one of the greatest and most practical of all cavalry leaders, had officers styled 'scout masters,' whose business it was to collect all possible information regarding the enemy, through scouts and spies, etc., and much of his success in war was traceable to the previous knowledge of the enemy's moves thus gained." [1] ]
9. Having LOCAL SPIES means employing the services of the
inhabitants of a district.
[Tu Mu says: "In the enemy's country, win people over by
kind treatment, and use them as spies."]
10. Having INWARD SPIES, making use of officials of the
enemy.
[Tu Mu enumerates the following classes as likely to do good service in this respect: "Worthy men who have been degraded from office, criminals who have undergone punishment; also, favorite concubines who are greedy for gold, men who are aggrieved at being in subordinate positions, or who have been passed over in the distribution of posts, others who are anxious that their side should be defeated in order that they may have a chance of displaying their ability and talents, fickle turncoats who always want to have a foot in each boat. Officials of these several kinds," he continues, "should be secretly approached and bound to one's interests by means of rich presents. In this way you will be able to find out the state of affairs in the enemy's country, ascertain the plans that are being formed against you, and moreover disturb the harmony and create a breach between the sovereign and his ministers." The necessity for extreme caution, however, in dealing with "inward spies," appears from an historical incident related by Ho Shih: "Lo Shang, Governor of I-Chou, sent his general Wei Po to attack the rebel Li Hsiung of Shu in his stronghold at P`i. After each side had experienced a number of victories and defeats, Li Hsiung had recourse to the services of a certain P`o-t`ai, a native of Wu-tu. He began to have him whipped until the blood came, and then sent him off to Lo Shang, whom he was to delude by offering to cooperate with him from inside the city, and to give a fire signal at the right moment for making a general assault. Lo Shang, confiding in these promises, march out all his best troops, and placed Wei Po and others at their head with orders to attack at P`o-t`ai's bidding. Meanwhile, Li Hsiung's general, Li Hsiang, had prepared an ambuscade on their line of march; and P`o-t`ai, having reared long scaling-ladders against the city walls, now lighted the beacon-fire. Wei Po's men raced up on seeing the signal and began climbing the ladders as fast as they could, while others were drawn up by ropes lowered from above. More than a hundred of Lo Shang's soldiers entered the city in this way, every one of whom was forthwith beheaded. Li Hsiung then charged with all his forces, both inside and outside the city, and routed the enemy completely." [This happened in 303 A.D. I do not know where Ho Shih got the story from. It is not given in the biography of Li Hsiung or that of his father Li T`e, CHIN SHU, ch. 120, 121.]
11. Having CONVERTED SPIES, getting hold of the enemy's spies and using them for our own purposes.
