The Essential Method of the Divine Cinnabar 玉洞大神丹砂真要诀

Originally compiled by Zhang Guo, a hermit of Guye Mountain in the Tang Dynasty.

Consisting of one volume, it is included in the Methods category of the The Dongshen Section in The Daozang.

This book is divided into seventeen grades, detailing the essential secrets of External Alchemy techniques. The first fourteen grades are mostly plagiarized from Chen Shaowei’s Tang Dynasty works The Precious Scripture of Great Cavern for Cultivating Truth: Mysterious Secrets of Refining and Subduing Spirit Cinnabar and The Precious Scripture of Great Cavern for Cultivating Truth: Mysterious Secrets of the Ninefold Return Golden Elixir, with slight additions, deletions, and revisions. Generally, they discuss the names and types of cinnabar, the medicines, cauldrons, furnaces, firing temperature, and production secrets for subduing and refining the Sevenfold Return Elixir, as well as methods for identifying the properties of mineral medicines (see the relevant entries for detailed content).

The last three grades include: Secrets of Cultivating Sagehood and Refining Alchemical Minerals, Secrets of Making Minor Divine Water, Secrets of Making the Great Elixir, and Secrets of the Alchemical Cauldron Absorbing Qi. The first two secrets describe the method of making the "Divine Water Jade Pond" and the production of required Xuanjing Powder (Mysterious Essence Powder) and Minor Divine Water. The latter two secrets elaborate on the method of making the "Divine Talisman White Snow Elixir" and the technique for the alchemical cauldron to absorb celestial qi. It is claimed that the Divine Water Jade Pond "can transform the five metals into treasures, and mercury dries up immediately upon contact with it"; the Divine Talisman White Snow Elixir, when ingested, "yields unpredictable and extraordinary merits with infinite creation—birds that eat it become phoenixes, snakes that consume it turn into dragons, and humans who take it attain immortality."