The essential factor of military success is speed, that is taking advantage of others' unpreparedness or lack of foresight, their failure to catch up, going by routes they do not expect, attacking where they are not on guard. This you cannot accomplish with hesitation.
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.
Spies cannot be usefully employed without a certain intuitive sagacity; They cannot be properly managed without benevolence and straightforwardness; Without subtle ingenuity of mind, one cannot make certain of the truth of their reports; Be subtle! be subtle! and use your spies for every kind of warfare; If a secret piece of news is divulged by a spy before the time is ripe, he must be put to death together with the man to whom the secret was told.
The good fighters of old first put themselves beyond the possibility of defeat, and then waited for an opportunity of defeating the enemy. To secure ourselves against defeat lies in our own hands, but the opportunity of defeating the enemy is provided by the enemy himself. Thus the good fighter is able to secure himself against defeat, but cannot make certain of defeating the enemy.
In all fighting, the direct method may be used for joining battle, but indirect methods will be needed in order to secure victory. Indirect tactics, efficiently applied, are inexhaustible as Heaven and Earth, unending as the flow of rivers and streams; like the sun and moon, they end but to begin anew; like the four seasons, they pass away to return once more.
There are roads which must not be followed, armies which must not be attacked, towns which must not be besieged, positions which must not be contested, commands of the sovereign which must not be obeyed.
Should one ask: 'how do I cope with a well-ordered enemy host about to attack me?' I reply: seize something he cherishes and he will conform to your desires.
It is only the enlightened ruler and the wise general who will use the highest intelligence of the army for the purposes of spying, and thereby they achieve great results.
It is said that if you know your enemies and know yourself, you will not be imperiled in a hundred battles; if you do not know your enemies but do know yourself, you will win one and lose one; if you do not know your enemies nor yourself, you will be imperiled in every single battle.