Mastering Yi Divination 易筮通变

Authored by Lei Siqi, a Taoist priest in the early Yuan Dynasty.

It consists of three volumes and is included in the Taixuan Section of The Daozang.

There is also a three-volume version incorporated in the Siku Quanshu (Complete Library of the Four Treasuries).

Mastering Yi Divination

This book is divided into five chapters: Divination, Hexagram Transformation, Nine and Six, Number Deduction, and Preparing Milfoil Stalks for Divination. Each chapter separately examines the origin of divination, explains the meaning of "hexagram transformation" as well as yang and yin lines, and illustrates the concept of "the fifty great expansion numbers" and the method of forming hexagrams through manipulating milfoil stalks. As a work largely dedicated to interpreting the divination techniques of the Zhouyi, it is hence titled Yishi Tongbian (Comprehensive Changes in Zhouyi Divination). Rooted in the five elements theory, its interpretations build on traditional divination systems while introducing innovative perspectives. Annotated Bibliography of the Siku Quanshu commends the book for "containing many original ideas and not being confined to old methods", a feature that also reflects the integration characteristics of Taoism thought and Zhouyi studies.