Tu Mu, after Tsʽao Kung the most important commentator on Sun Tzǔ, composed the preface to his edition38 about the middle of the ninth century. After a somewhat lengthy defence of the military art,39 he comes at last to Sun Tzǔ himself, and makes one or two very startling assertions:—“The writings of Sun Wu,” he says, “originally comprised several hundred thousand words, but Tsʽao Tsʽao, the Emperor Wei, pruned away all redundancies and wrote out the essence of the whole, so as to form a single book in 13 chapters.”40 He goes on to remark that Tsʽao Tsʽao’s commentary on Sun Tzǔ leaves a certain proportion of difficulties unexplained.41 This, in Tu Mu’s opinion, does not necessarily imply that he was unable to furnish a complete commentary. According to the Wei Chih, Tsʽao himself wrote a book on war in something over 100,000 words, known as the 新書. It appears to have been of such exceptional merit that he suspects Tsʽao to have used for it the surplus material which he had found in Sun Tzǔ. He concludes, however, by saying: “The Hsin Shu is now lost, so that the truth cannot be known for certain.”42
Tu Mu’s conjecture seems to be based on a passage in the 漢官解詁 “Wei Wu Ti strung together Sun Wu’s Art of War,”43 which in turn may have resulted from a misunderstanding of the final words of Tsʽao Kung’s preface: 故撰為略解焉. This, as Sun Hsing-yen points out,44 is only a modest way of saying that he made an explanatory paraphrase,45 or in other words, wrote a commentary on it. On the whole, this theory has met with very little acceptance. Thus, the 四庫全書 says:46 “The mention of the 13 chapters in the Shih Chi shows that they were in existence before the Han Chih, and that latter accretions are not to be considered part of the original work. Tu Mu’s assertion can certainly not be taken as proof.”47
There is every reason to suppose, then, that the 13 chapters existed in the time of Ssǔ-ma Chʽien practically as we have them now. That the work was then well known he tells us in so many words: “Sun Tzǔ’s 13 Chapters and Chʽi’s Art of War are the two books that people commonly refer to on the subject of military matters. Both of them are widely distributed, so I will not discuss them here.”48 But as we go further back, serious difficulties begin to arise. The salient fact which has to be faced is that the Tso Chuan, the greatest contemporary record, makes no mention whatsoever of Sun Wu, either as a general or as a writer. It is natural, in view of this awkward circumstance, that many scholars should not only cast doubt on the story of Sun Wu as given in the Shih Chi, but even show themselves frankly skeptical as to the existence of the man at all. The most powerful presentment of this side of the case is to be found in the following disposition by 葉水心 Yeh Shui-hsin:49—
It is stated in Ssǔ-ma Chʽien’s history that Sun Wu was a native of the Chʽi State, and employed by Wu; and that in the reign of Ho Lu he crushed Chʽu, entered Ying, and was a great general. But in Tso’s Commentary no Sun Wu appears at all. It is true that Tso’s Commentary need not contain absolutely everything that other
