Laying Plans · Five Factors and Seven Calculations
Sun Tzŭ said: The art of war is of vital importance to the State. It is a matter of life and death, a road either to safety or to ruin. Hence it is a subject of inquiry which can on no account be neglected. The art of war, then, is governed by five constant factors, to be taken into account in one's deliberations.
War decides whether a state lives or dies, so it has to be studied carefully. Compare both sides on five things first: unity, timing, ground, leadership and organisation, and get at the real situation.
The Use of Spies · Five Types of Spies
Having local spies means making use of officials of the enemy. Having inward spies means making use of spies of the enemy. Having converted spies means getting hold of the enemy's spies and using them for our own purposes. Having doomed spies means doing certain things openly for purposes of deception, and allowing our spies to know of them and report them to the enemy. Surviving spies means those who bring back news from the enemy's camp.
Five kinds of spies: local people, enemy officials, turned enemy agents, those who carry false reports, and those who come back alive with news. Intelligence is not one person's job.