The art of using troops is this:
......When ten to the enemy's one, surround him;
......When five times his strength, attack him;
......If double his strength, divide him;
......If equally matched you may engage him;
......If weaker numerically, be capable of withdrawing;
......And if in all respects unequal, be capable of eluding him,
..........for a small force is but booty for one more powerful.
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.
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.
War is a matter of vital importance to the state; the province of life or death; the road to survival or ruin. It is mandatory that it be thoroughly studied.
Regard your soldiers as your children, and they will follow you into the deepest valleys; look upon them as your own beloved sons, and they will stand by you even unto death.
Should the enemy strengthen his van, he will weaken his rear; should he strengthen his rear, he will weaken his van; should he strengthen his left, he will weaken his right; should he strengthen his right, he will weaken his left. If he sends reinforcements everywhere, he will everywhere be weak.
To plan secretly, to move surreptitiously, to foil the enemy's intentions and balk his schemes, so that at last the day may be won without shedding a drop of blood.
So a military force has no constant formation, water has no constant shape: the ability to gain victory by changing and adapting according to the opponent is called genius.
Thus it is that in war the victorious strategist only seeks battle after the victory has been won, whereas he who is destined to defeat first fights and afterwards looks for victory.