to be without humanity. Such a person is no general; he is no assistance to his lord; he is no master of victory.
The enlightened ruler and the wise general who act, win, and are distinguished beyond the common, are informed beforehand.
This knowledge is not to be got by calling on gods and demons; nor does it come of past experience nor calculation. It is through men that knowledge of the enemy is gained.
Now the five kinds of spies are these: village spies, inner spies, converted spies, death spies, living spies.
If these five means be employed simultaneously, none can discover their working. This is called the Mysterious Thread: it is the Lord’s Treasure.
Village spies are such people of the country as give information.
Inner spies are those of the enemy's officials employed by us.
Converted spies are those of the enemy’s spies in our pay.
