The Understanding and Uses of the “Day Court Diagram” in Qin-Han Hemerology and Calendrical Astrology

Abstract

Archaeological discoveries related to hemerology and calendrical astrology have drawn attention to the existence of a square geometric pattern consisting in its simplest form of a central cross and four right angles in the corners opening to the exterior. In this paper I examine the most common terms used in modern research to name the diagram. I then rank the existing diagrams based on the specific contexts for which they were designed, along with a presentation of the technical features of each diagram. Finally, I show how the various forms taken by these diagrams may lead to a better understanding of their meaning and functions and provide preliminary answers to questions such as the purpose of inserting a diagram in a technical text, the advantage of a diagram compared with a list or a table, and more generally, the relationship between text and image in the excavated manuscripts.