se who were called skillful leaders of old knew how
to drive a wedge between the enemy's front and rear;

[More literally, "cause the front and rear to lose touch
with each other."]

to prevent co-operation between his large and small divisions; to
hinder the good troops from rescuing the bad, the officers from
rallying their men.
16. When the enemy's men were united, they managed to keep
them in disorder.
17. When it was to their advantage, they made a forward
move; when otherwise, they stopped still.

[Mei Yao-ch`en connects this with the foregoing: "Having
succeeded in thus dislocating the enemy, they would push forward
in order to secure any advantage to be gained; if there was no
advantage to be gained, they would remain where they were."]

18. If asked how to cope with a great host of the enemy in
orderly array and on the point of marching to the attack, I
should say: "Begin by seizing something which your opponent
holds dear; then he will be amenable to your will."

[Opinions differ as to what Sun Tzu had in mind. Ts`ao Kung
thinks it is "some strategical advantage on which the enemy is
depending." Tu Mu says: "The three things which an enemy is
anxious to do, and on the accomplishment of which his success
depends, are: (1) to capture our favorable positions; (2) to
ravage our cultivated land; (3) to guard his own communications."
Our object then must be to thwart his plans in these three
directions and thus render him helpless. [Cf. III. ss. 3.] By
boldly seizing the initiative in this way, you at once throw the
other side on the defensive.]

19. Rapidity is the essence of war:

[According to Tu Mu, "this is a summary of leading
principles in warfare," and he adds: "These are the profoundest
truths of military science, and the chief business of the
general." The following anecdotes, told by Ho Shih, shows the
importance attached to speed by two of China's greatest generals.
In 227 A.D., Meng Ta, governor of Hsin-ch`eng under the Wei
Emperor Wen Ti, was meditating defection to the House of Shu, and
had entered into correspondence with Chu-ko Liang, Prime Minister
of that State. The Wei general Ssu-ma I was then military
governor of Wan, and getting wind of Meng Ta's treachery, he at
once set off with an army to anticipate his revolt, having
previously cajoled him by a specious message of friendly import.
Ssu-ma's officers came to