One thing to be noticed in the above is the explicit statement that the 13 chapters were specially composed for King Ho Lu. This is supported by the internal evidence of I. § 15, in which it seems clear that some ruler is addressed. In the bibliographic section of the _Han Shu_, there is an entry which has given rise to much discussion: "The works of Sun Tzŭ of Wu in 82 _p’ien_ (or chapters), with diagrams in 9 _chuan_." It is evident that this cannot be merely the 13 chapters known to Ssu-ma Ch’ien, or those we possess today. Chang Shou-chieh refers to an edition of Sun Tzŭ’s _Art of War_ of which the "13 chapters" formed the first _chuan_, adding that there were two other _chuan_ besides. This has brought forth a theory, that the bulk of these 82 chapters consisted of other writings of Sun Tzŭ—we should call them apocryphal—similar to the _Wen Ta_, of which a specimen dealing with the Nine Situations [15] is preserved in the _T’ung Tien_, and another in Ho Shin’s commentary. It is suggested that before his interview with Ho Lu, Sun Tzŭ had only written the 13 chapters, but afterwards composed a sort of exegesis in the form of question and answer between himself and the King. Pi I-hsun, the author of the _Sun Tzŭ Hsu Lu_, backs this up with a quotation from the _Wu Yüeh Ch’un Ch’iu:_ "The King of Wu summoned Sun Tzŭ, and asked him questions about the art of war. Each time he set forth a chapter of his work, the King could not find words enough to praise him." As he points out, if the whole work was expounded on the same scale as in the above-mentioned fragments, the total number of chapters could not fail to be considerable. Then the numerous other treatises attributed to Sun Tzŭ might be included. The fact that the _Han Chih_ mentions no work of Sun Tzŭ except the 82 _p’ien_, whereas the Sui and T’ang bibliographies give the titles of others in addition to the "13 chapters," is good proof, Pi I-hsun thinks, that all of these were contained in the 82 _p’ien_. Without pinning our faith to the accuracy of details supplied by the _Wu Yüeh Ch’un Ch’iu_, or admitting the genuineness of any of the treatises cited by Pi I-hsun, we may see in this theory a probable solution of the mystery. Between Ssu-ma Ch’ien and Pan Ku there was plenty of time for a luxuriant crop of forgeries to have grown up under the magic name of Sun Tzŭ, and the 82 _p’ien_ may very well represent a collected edition of these lumped together with the original work. It is also possible, though less likely, that some of them existed in the time of the earlier historian and were purposely ignored by him. [16]