The Art of War

 6. An army may march great distances without distress,
    if it marches through country where the enemy is not.

 7. You can be sure of succeeding in your attacks
    if you only attack places which are undefended.You can
    ensure the safety of your defense if you only hold
    positions that cannot be attacked.

 8. Hence that general is skillful in attack whose
    opponent does not know what to defend; and he is skillful
    in defense whose opponent does not know what to attack.

 9. O divine art of subtlety and secrecy!  Through you
    we learn to be invisible, through you inaudible;
    and hence we can hold the enemy's fate in our hands.

10. You may advance and be absolutely irresistible,
    if you make for the enemy's weak points; you may retire
    and be safe from pursuit if your movements are more rapid
    than those of the enemy.

11. If we wish to fight, the enemy can be forced
    to an engagement even though he be sheltered behind a high
    rampart and a deep ditch.  All we need do is attack
    some other place that he will be obliged to relieve.

12. If we do not wish to fight, we can prevent
    the enemy from engaging us even though the lines
    of our encampment be merely traced out on the ground. 
    All we need do is to throw something odd and unaccountable
    in his way.

13. By discovering the enemy's dispositions and remaining
    invisible ourselves, we can keep our forces concentrated,
    while the enemy's must be divided.

14. We can form a single united body, while the
    enemy must split up into fractions.  Hence there will
    be a whole pitted against separate parts of a whole,
    which means that we shall be many to the enemy's few.

15. And if we are able thus to attack an inferior force
    with a superior one, our opponents will be in dire straits.

16. The spot where we intend to fight must not be
    made known; for then the enemy will have to prepare
    against a possible attack at several different points;
    and his forces being thus distributed in many directions,
    the numbers we shall have to face at any given point will
    be proportionately few.

17. For 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.

18. Numerical weakness comes from having to prepare
    against possible attacks; numerical strength, from compelling
    our adversary to make these preparations against us.

19. Knowing the place and the time of the coming battle,
    we may concentrate from the greatest distances in order
    to fight.

20. But if neither time nor place be known,
    then the left wing will be impotent to succor the right,
    the right equally impotent to succor the left, the van
    unable to relieve the rear, or the rear to support the van. 
    How much more so if the furthest portions of the army are
    anything under a hundred LI apart, and even the nearest
    are separated by several LI!

21. Though according to my estimate the soldiers
    of Yueh exceed our own in number, that shall advantage
    them nothing in the matter of victory.  I say then
    that victory can be achieved.

22. Though the enemy be stronger in numbers, we may
    prevent him from fighting.  Scheme so as to discover
    his plans and the likelihood of their success.

23. Rouse him, and learn the principle of his
    activity or inactivity.  Force him to reveal himself,
    so as to find out his vulnerable spots.

24. Carefully compare the opposing army with your own,
    so that you may know where strength is superabundant
    and where it is deficient.

25. In making tactical dispositions, the highest pitch
    you can attain is to conceal them; conceal your dispositions,
    and you will be safe from the prying of the subtlest spies,
    from the machinations of the wisest brains.

26. How victory may be produced for them out of the enemy's
    own tactics--that is what the multitude cannot comprehend.