Asked if an army can be made to imitate the _shuai-jan_, I should
answer, Yes. For the men of Wu and the men of Yüeh are enemies;
yet if they are crossing a river in the same boat and are caught
by a storm, they will come to each other’s assistance just as the
left hand helps the right.
These two paragraphs are extremely valuable as evidence of the date of
composition. They assign the work to the period of the struggle
between Wu and Yüeh. So much has been observed by Pi I-hsün. But what
has hitherto escaped notice is that they also seriously impair the
credibility of Ssŭ-ma Ch‘ien’s narrative. As we have seen above, the
first positive date given in connection with Sun Wu is 512 B.C. He is
then spoken of as a general, acting as confidential adviser to Ho Lu,
so that his alleged introduction to that monarch had already taken
place, and of course the 13 chapters must have been written earlier
still. But at that time, and for several years after, down to the
capture of Ying in 506, 楚 Ch‘u, and not Yüeh, was the great hereditary
enemy of Wu. The two states, Ch‘u and Wu, had been constantly at war
for over half a century,[74] whereas the first war between Wu and Yüeh
was waged only in 510,[75] and even then was no more than a short
interlude sandwiched in the midst of the fierce struggle with Ch‘u.
Now Ch‘u is not mentioned in the 13 chapters at all. The natural
inference is that they were written at a time when Yüeh had become the
prime antagonist of Wu, that is, after Ch‘u had suffered the great
humiliation of 506. At this point, a table of dates may be found useful.