Chapter Six: Weakness and Strength 
Sun-tzu said:
Generally the one who first occupies the battlefield awaiting the enemy is at ease;
the one who comes later and rushes into battle is fatigued.
Therefore
those skilled in warfare move the enemy,
and are not moved by the enemy.
Getting the enemy to approach on his own accord is a matter of showing him advantage;
stopping him from approaching is a matter of showing him harm.
Therefore, if the enemy is at ease, be able to exhaust him;
if the enemy is well fed, be able to starve him;
if the enemy is settled, be able to move him;
appear at places where he must rush to defend, and rush to places where he least expects.
To march over a thousand li without becoming distressed,
march over where the enemy is not present.
To be certain to take what you attack,
attack where the enemy cannot defend.
To be certain of safety when defending,
defend where the enemy cannot attack.
Therefore,
against those skilled in attack,
the enemy does not know where to defend;
against those skilled in defense,
the enemy does not know where to attack.
Subtle! Subtle!
They become formless.
Mysterious! Mysterious!
They become soundless.
Therefore,
they are the masters of the enemy's fate.
To achieve an advance that cannot be hampered,
rush to his weak points.
To achieve a withdrawal that cannot be pursued,
depart with superior speed.
Therefore, if we want to do battle,
even if the enemy is protected by high walls and deep moats, he cannot but do battle,
because we attack what he must rescue.
If we do not want to do battle,
even if we merely draw a line on the ground,
he will not do battle, because we divert his movements.
Therefore, if we can make the enemy show his position while we are formless,
we will be at full force while the enemy is divided.
If our army is at full force and the enemy is divided,
then we will attack him at ten times his strength.
Therefore, we are many and the enemy few.
If we attack our many against his few,
the enemy will be in dire straits.
The place of battle must not be made known to the enemy.
If it is not known,
then the enemy must prepare to defend many places.
If he prepares to defend many places,
then the forces will be few in number.
Therefore, if he prepares to defend the front,
the back will be weak.
If he prepares to defend the back,
the front will be weak.
If he prepares to defend the left,
the right will be weak.
If he prepares to defend the right,
the left will be weak.
If he prepares to defend everywhere,
everywhere will be weak.
The few are those preparing to defend against others,
the many are those who make others prepare to defend against them.
Therefore, if one knows the place of battle and the day of battle,
he can march a thousand li and do battle.
If one does not know the place of battle and the day of battle,
then his left cannot aid his right,
and his right cannot aid his left;
his front cannot aid his back,
and his back cannot aid his front.
How much less so if he is separated by tens of li, or even a few li.
Based on my calculations,
though Yueh's troops were many,
what advantage was this to them in respect to victory?
Therefore I say,
victory can be achieved.
Though the enemy is many,
he can be prevented from doing battle.
Therefore,
know the enemy's plans and calculate their strengths and weaknesses.
Provoke him,
to know his patterns of movement.
Determine his position, to know the ground of death and of life.
Probe him, to know where he is strong
and where he is weak.
The ultimate skill is to take up a position where you are formless.
If you are formless,
the most penetrating spies will not be able to discern you,
or the wisest counsels will not be able to do calculations against you.
With formation, the army achieves victories
yet they do not understand how.
Everyone knows the formation by which you achieved victory,
yet no one knows the formations by which you were able to create victory.
Therefore, your strategy for victories in battle is not repetitious,
and your formations in response to the enemy are endless.
The army's formation is like water.
The water's formation avoids the high and rushes to the low.
So an army's formation avoids the strong and rushes to the weak.
Water's formation adapts to the ground when flowing.
So then an army's formation adapts to the enemy to achieve victory.
Therefore,
an army does not have constant force, or have constant formation.
Those who are able to adapt and change in accord with the enemy and achieve victory are called divine.
Therefore, of the five elements, none a constant victor,
of the four seasons,
none has constant position;
the sun has short and long spans,
and the moon waxes and wanes.
