Thus one who is skilful at keeping the enemy on the move maintains
deceitful appearances, according to which the enemy will act.
Ts‘ao Kung’s note is 見羸形也 “Make a display of weakness and
want,” but Tu Mu rightly points out that 形 does not refer only to
weakness: “If our force happens to be superior to the enemy’s,
weakness may be simulated in order to lure him on; but if
inferior, he must be led to believe that we are strong, in order
that he may keep off. In fact, all the enemy’s movements should be
determined by the signs that we choose to give him.” The following
anecdote of 孫臏 Sun Pin, a descendant of Sun Wu, is related at
length in the 史記, chap. 65: In 341 B.C., the 齊 Ch‘i State being
at war with 魏 Wei, sent 田忌 T‘ien Chi and Sun Pin against the
general 龐涓 P‘ang Chüan, who happened to be a deadly personal
enemy of the latter. Sun Pin said: “The Ch‘i State has a
reputation for cowardice, and therefore our adversary despises us.
Let us turn this circumstance to account.” Accordingly, when the
army had crossed the border into Wei territory, he gave orders to
show 100,000 fires on the first night, 50,000 on the next, and the
night after only 20,000. P‘ang Chüan pursued them hotly, saying to
himself: “I knew these men of Ch‘i were cowards: their numbers
have already fallen away by more than half.” In his retreat, Sun
Pin came to a narrow defile, which he calculated that his pursuers
would reach after dark. Here he had a tree stripped of its bark,
and inscribed upon it the words: “Under this tree shall P‘ang
Chüan die.” Then, as night began to fall, he placed a strong body
of archers in ambush near by, with orders to shoot directly they
saw a light. Later on, P‘ang Chüan arrived at the spot, and
noticing the tree, struck a light in order to read what was
written on it. His body was immediately riddled by a volley of
arrows, and his whole army thrown into confusion. [The above is Tu
Mu’s version of the story; the _Shih Chi_, less dramatically but
probably with more historical truth, makes P‘ang Chüan cut his own
throat with an exclamation of despair, after the rout of his army.]
He sacrifices something, that the enemy may snatch at it.
予 here = 與.