Preface to the Illustrated Commentary on the Detailed Calculations of the Nine Chapters

The preface discusses the historical significance of the Jiuzhang Suanshu Nine Chapters on the Mathematical Art.

Just as the preface to the Siyuan Yujian Jade Mirror of the Four Unknowns states that the maps and writings of the Yellow River and Luo River revealed their secrets, the Yellow Emperor's Nine Chapters Nine Chapters on the Mathematical Art recorded them in a book. There are nine chapters, containing two hundred and forty-six mathematical procedures, beginning with "Field Measurement" and ending with "Right-Angled Triangles." They encompass the three realms of heaven, earth, and humanity, and connect with all things. Those who speak of mathematics cannot escape these principles. During the Tang Dynasty, a department of mathematics was established, where the Nine Chapters and the Haidao Suanjing Sea Island Mathematical Manual were studied together for a three-year term. The examinations required solving three problems from the Nine Chapters and one from the Sea Island. This was not only to display the calculations but to clarify their meanings. Since that time, the department of mathematics was abolished, and the book became obscured. In recent times, those known for their mathematical skills, such as Wang Yinxu and Mei Dingjiu, had not yet seen these texts. Later, our kinsman Dai Dongyuan, while compiling the Siku Quanshu Complete Library of the Four Treasuries, recovered a copy from the Yongle Dadian Great Canon of the Yongle Era, which was printed by the Kong family of Qufu and again by the Qu family of Changshu. Ancient learning was thus revived, yet a full explanation was still lacking. Master Li Yunmen of Zhongxiang was widely...