Essence of Inner Enlightenment 悟玄篇

Composed by Yu Dongzhen, a Taoist priest of the Yuan Dynasty.

It consists of one scroll and is included in the Tai Xuan Section of The Daozang.

This book expounds the cultivation methods of Internal Alchemy. The author claimed that he "obtained the method of refining yin with yang from his master in ancient Hangzhou", and thus compiled this work. The book is divided into chapters including Form Transformation, Qi Transformation, Oral Instructions for Sitting Practice, Flaring Fire and Overflowing Water, Bathing, The Mysterious Pass, Medicinal Ingredients, Fire Timing, the Central Palace, and Embracing the One.

Essence of Inner Enlightenment

It states that those who refine the Golden Elixir must first recognize the origin of their physical body and establish it as the foundation of the elixir. Next, they must reverse the Five Elements, and in turn refine essence into Qi, refine Qi into spirit, refine spirit to return to emptiness, ultimately "smashing the void to achieve the ultimate goal".

Its initial practice method is sitting in oblivion with closed eyes: "Forget the physical form externally and be unburdened by material things; forget the mind internally and be unoccupied by worldly affairs. Abide in the inner core as if holding it, yet as if not holding it; guard it as if protecting it, yet as if not protecting it."

After a long time of practice, the mind will be calm and thoughts steady, and yang Qi will generate naturally. It rises from the coccyx at the waist up the Governor Vessel to the crown of the head, where yin and yang Qi converge and blend, then descend to the tip of the tongue, and be swallowed into the Central Palace. This practice should be performed three or four times a day.

"The initial pass (refining essence into Qi) takes a hundred days, followed by a month of bathing; the middle pass (refining Qi into spirit) takes a hundred days, with the same bathing period as before; the upper pass (refining spirit to return to emptiness) takes a hundred days, after which the fire timing reaches its end. One achieves spiritual transformation through embryo separation, embraces the One and nurtures the immortal child, and upon completing nine years of practice, ascends to heaven in broad daylight."

The book quotes the words of Zhang Boduan, Shi Xinglin and Bai Yuchan as evidence, and its alchemical method evidently belongs to the Southern Sect of the Golden Elixir school.