Essence of Elixir Refinement 修丹妙用至理论

The author is unknown.

It was probably compiled in the Northern Song Dynasty. Consisting of one scroll, it is included in the Methods category of the Dongzhen Section of The Daozang.

This text expounds on the theories and methods of elixir refining, divided into nine chapters. The chapters are in the following order: Trigram Qi, Fire Control, Medicinal Formulas, Resolving Doubts, Jia and Geng, Five Elements, Medicinal Verification, Implement Preparation, and Nine Cycles of Refinement.

It generally states that the construction of alchemy altars, chambers, stoves and cauldrons, as well as the fire control for elixir refining, must all emulate the numerical patterns of heaven and earth's creation and transformation, and the generation and operation of all things. It also emphasizes that lead and mercury, the alchemical medicinal ingredients, are not mortal substances in the world, but originate prior to heaven and earth. True lead and true mercury are inherently compatible, and through the communion of Yin and Yang, the Golden Elixir is formed.

The refining process is set to a three-year period: one year yields the Minor Reverted Elixir, two years the Middle Reverted Elixir, and three years the Great Reverted Elixir. The text quotes the words of Zhang Guo and Liu Haichan, and also touches on the doctrines of Internal Alchemy.