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