Guide to the Inner Axis 陈虚白规中指南

Written by Chen Chongsu, styled Xubaizi, a Taoist priest of the Yuan Dynasty. It consists of two volumes and is included in the Methods category of The Dongzhen Section within The Daozang.

The upper volume explains the practices of Internal Alchemy, divided into nine stages according to the order of practice: Stopping Thoughts, Gathering the Medicine, Recognizing the Furnace, Entering the Medicine and Igniting the Fire, Union of Kan and Li, Union of Qian and Kun, Assembling the Fire Phasing, Yang Spirit Emerging from the Womb, and Forgetting the Spirit to Unite with Emptiness.

Each stage is accompanied by diagrams, illustrations and odes.

The lower volume quotes teachings of northern and southern masters such as Zhang Ziyang and Ma Danyang, expounding the Three Essentials of Internal Alchemy: the Mysterious Barrier (Xuanpin), the Medicine, and the Fire Phasing.

It holds that the Mysterious Pass (Xuanguan Yiqiao) is the method of leading qi back to spirit and gathering it in the thought; its essential principle lies in the union of original essence and original qi, with original spirit abiding therein, so that the three merge into one.

It further emphasizes that elixir cultivation takes true nature as the ruler: “Taking stillness as the root, and concentration as the foundation. Once they revolve, the heavenly mechanism moves of itself in an instant. Without seeking the center of the compass, it is naturally in the center; without seeking fetal breathing, fetal breathing arises naturally; the medicine is not sought yet is born of itself; the fire is not sought yet emerges of itself.”

This view draws upon the doctrines of the Quanzhen school.