When you surround an army, leave an outlet free.
This does not mean that the enemy is to be allowed to escape. The
object, as Tu Mu puts it, is 示以生路令無必死之心 “to make him
believe that there is a road to safety, and thus prevent his
fighting with the courage of despair.” Tu Mu adds pleasantly:
因而擊之 “After that, you may crush him.”
Do not press a desperate foe too hard.
For 迫, the _T‘u Shu_ reads 追 “pursue.” Ch‘ên Hao quotes the
saying: 鳥窮則搏獸窮則噬 “Birds and beasts when brought to bay will
use their claws and teeth.” Chang Yü says: 敵若焚舟破釜決一戰則不可逼
迫來 “If your adversary has burned his boats and destroyed his
cooking-pots, and is ready to stake all on the issue of a battle,
he must not be pushed to extremities.” The phrase 窮宼 doubtless
originated with Sun Tzŭ. The _P‘ei Wên Yün Fu_ gives four examples
of its use, the earliest being from the _Ch‘ien Han Shu_, and
I have found another in chap. 34 of the same work. Ho Shih
illustrates the meaning by a story taken from the life of 符彥卿 Fu
Yen-ch‘ing in ch. 251 of the 宋史. That general, together with his
colleague 杜重威 Tu Chung-wei, was surrounded by a vastly superior
army of Khitans in the year 945 A.D. The country was bare and
desert-like, and the little Chinese force was soon in dire straits
for want of water. The wells they bored ran dry, and the men were
reduced to squeezing lumps of mud and sucking out the moisture.
Their ranks thinned rapidly, until at last Fu Yen-ch‘ing
exclaimed: “We are desperate men. Far better to die for our
country than to go with fettered hands into captivity!” A strong
gale happened to be blowing from the north-east and darkening the
air with dense clouds of sandy dust. Tu Chung-wei was for waiting
until this had abated before deciding on a final attack; but
luckily another officer, 李守貞 Li Shou-chêng by name, was quicker
to see an opportunity, and said: “They are many and we are few,
but in the midst of this sandstorm our numbers will not be
discernible; victory will go to the strenuous fighter, and the
wind will be our best ally.” Accordingly, Fu Yen-ch‘ing made a
sudden and wholly unexpected onslaught with his cavalry, routed
the barbarians and succeeded in breaking through to safety.
[Certain details in the above account have been added from the
歴代紀事年表, ch. 78.]