Intelligence and Espionage
Generally, raising an army of 100,000 and advancing it 1000 li, the expenses to the people and the nation’s resources are 1000 gold pieces a day.
Those in commotion internally and externally, those exhausted on the roads, and those unable to do their daily work are 700,000 families.
Two sides remain in standoff for several years in order to do battle for a decisive victory on a single day. Yet one refusing to outlay 100 pieces of gold and thereby does not know the enemy’s situation is the height of inhumanity. This one is not the general of the people, a help to the ruler, or the master of victory.
What enables the enlightened rulers and good generals to conquer the enemy at every move and achieve extraordinary success is foreknowledge. Foreknowledge cannot be elicited from ghosts and spirits; it cannot be inferred from comparison of previous events, or from the calculations of the heavens, but must be obtained from people who have knowledge of the enemy’s situation.
Therefore there are five kinds of spies used:
- Local spies
- Internal spies
- Double spies
- Dead spies
- Living spies.
When all five are used, and no one knows their Way, it is called the divine organization, and is the ruler’s treasure.
- For local spies, we use the enemy’s people.
- For internal spies we use the enemy’s officials.
- For double spies we use the enemy’s spies.
- For dead spies we use agents to spread misinformation to the enemy.
- For living spies, we use agents to return with reports.
Therefore, of those close to the army, none is closer than spies, no reward more generously given, and no matter in greater secrecy. 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! There is nowhere that spies cannot be used. If a spy’s activities are leaked before they are to begin, the spy and those who know should be put to death.
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. 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. 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.
This knowledge depends on the double spies. Therefore, you must treat them with the utmost generosity. In ancient times, the rise of the Yin dynasty was due to I Chih, who served the house of Hsia; the rise of the Chou dynasty was due to Lu Ya, who served the house of Yin.
Therefore, enlightened rulers and good generals who are able to obtain intelligent agents as spies are certain for great achievements.
This is essential for warfare, and what the army depends on to move.