In this text-reading, we will attempt to make our way through the first half (or so) of the Luminous Inception system (Jingchu li 景初曆), a manual of li mathematical astronomy from 237 CE. The Luminous Inception system saw use from the third to fifth centuries CE; the concepts and mathematics involved are very simple; and, in as much as the Chinese li manual genre changed very little from the first to sixteenth centuries CE, this manual serves as an excellent entrée into the greater genre. This session is intended as an introduction to reading key materials in the Chinese astral sciences through which we may begin to discuss how and what mathematics were deployed for astronomical purposes.