Be the first to seize intersecting ground, that is ground which lies the intersections of borders or intersections of main thoroughfares of commerce and travel. Your occupation of it gives you access to all who border it and all who would covet it. On intersecting ground, if you establish alliances you are safe, if you lose alliances you are in peril.

It is essential to seek out enemy agents who have come to conduct espionage against you and to bribe them to serve you. Give them instructions and care for them. Thus doubled agents are recruited and used.

If I wish to engage, then the enemy, for all his high ramparts and deep moat, cannot avoid engagement; I attack that which he is obliged to rescue.

With regard to narrow passes, if you can occupy them first, let them be strongly garrisoned and await the advent of the enemy.

The good fighter is able to secure himself against defeat, but cannot make certain of defeating the enemy.

The supreme art of war is to subdue the enemy without fighting.

The end and aim of spying in all its five varieties is knowledge of the enemy; and this knowledge can only be derived, in the first instance, from the converted spy. Hence it is essential that the converted spy be treated with the utmost liberality.