- Spies cannot be usefully employed without a certain intuitive sagacity.
[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 passage."]
- They cannot be properly managed without benevolence and straightforwardness.
[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."]
- 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."]
- Be subtle! be subtle! and use your spies for every kind of business.
[Cf. VI. § 9.]
- 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.