孫 子 兵 法 Sun Zi – L'Art de la guerre

1. 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."