13. The Use of Spies
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."