[13.10] Therefore, of those close to the army, none is closer than spies, no reward more generously given, and no matter in greater secrecy.
[13.11] Only the wisest ruler can use spies; only the most benevolent and upright general* can use spies, and only the most alert and observant person can get the truth using spies. It is subtle, subtle!
[13.12] There is nowhere that spies cannot be used.
[13.13] If a spy's activities are leaked before they are to begin, the spy and those who know should be put to death.*
[13.14] Generally, if you want to attack an army, besiege a walled city, assassinate individuals, you must know the identities of the defending generals, assistants, associates, gate guards, and officers.
[13.15] You must have spies seek and learn them. You must seek enemy spies.* Bribe them, and instruct and retain them. Therefore, double spies can be obtained and used.
[13.16] From their knowledge, you can obtain local and internal spies. From their knowledge, the dead spies can spread misinformation to the enemy. From their knowledge, our living spies can be used as planned. The ruler must know these five kinds of espionage.*
[13.17] This knowledge depends on the double spies. Therefore, you must treat them with the utmost generosity.
13.11 benevolent and upright general. To use spies successfully, be generous to them, devoted to the fight's moral purpose, and highly discerning (to distinguish between loyal and disloyal spies).