Sun Tzǔ 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. 畢以珣 Pi I-hsün , the author of the 孫子敘錄 Sun Tzǔ Hsü Lu , backs this up with a quotation from the Wu Yüeh Chʽun Chʽiu : “The King of Wu summoned Sun Tzǔ , 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.” 34 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. 35