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; local spies, inner spies, converted spies, death spies, living spies.
If these five means be employed simultaneously, none can discover their working. It is called the Mysterious Thread: it is the Lord’s Treasure.
Social 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.
Death[1] spies are sent to misinform the enemy; and to spread false reports through our spies already in the enemy’s lines.
Living spies return to report.
In connection with the main army, spies should be treated with the greatest confidence; and in dealing out reward, they should receive the most generous treatment. All matters relating to spies are secret.
Without infinite capacity in the general, the employment of spies is impossible. Their treatment requires
benevolence and uprightness. Except they be treated
- ↑ So called because they are put to death when the enemy finds out that he has been tricked.
