Sun Tzu - The Five Types of Spies

Sun Tzu - On the Use of Secret Agents - the Five Types of Spies - 

Hence the use of spies, of whom there are five classes: (1) Native - Local spies; (2) Internal - inward spies; (3) Double - converted spies; (4) Expendable - doomed spies; (5) Living - surviving spies. 

Hence the use of spies, of whom there are five classes:

(1) Native - Local spies means employing the services of the civilian inhabitants of a district; Local Spies: Recruited from the general population of the enemy state.

 (2) Internal - inward spies; making use of officials of the enemy. Inside Spies: Disaffected officials from the government of the enemy state, even include relatives of persecuted officials. The treatise elaborates on ways to identify ‘Inside Spies’ from a host of situations, and whom to approach - the ambitious, the dejected, the suppressed, the punished and the duplicitous.

(3) Double Agents - converted spies; getting hold of the enemy's spies and using them for our own purposes. Reverse Spies: They are enemy agents who have been turned (with bribes, promises, ideals and so one), and they now spy against their old master or send back false information.

(4) doomed spies; Expendable spies - are employed to spread disinformation outside the state. Provide our expendable spies with false information and have them leak it to enemy agents, doing certain things openly for purposes of deception, and allowing our spies to know of them and report them to the enemy.  Dead Spies: They are dispensable agents who are fed false information by the general. This false information is eventually found out and the spy is executed by the enemy.

(5) surviving spies are those who bring back news from the enemy's camp. Living Spies: They are the alpha spies - iron-willed but simple in appearance, they never let their guard down and operate effectively in enemy territory. They are immune to betrayal and seduction but practice it on others with ease.

When these five kinds of spy are all at work, none can discover the secret system. This is called the Divine Skein - or "divine manipulation of the threads." It is the treasure of the sovereign and their most precious faculty.