The Zhi Xuan Pian 指玄篇 Treatise on Pointing to the Mystery

Zhi Xuan Pian (Treatise on Pointing to the Mystery) is one of the Taoist inner alchemy works, consisting of two parts. It is included in Volume 6 of Zang Wai Dao Shu (Daoist Books Outside the Taoist Canon), attributed to Lü Dongbin of the Tang Dynasty, with annotations by Bai Yuchan of the Song Dynasty.

The first part of Zhi Xuan Pian, Xie Ziyang Zhenren Shu (A Letter in Gratitude to True Person Ziyang), expresses the author’s understanding of the alchemy path in the form of a "memorial to a superior". First, the author points out that there is no two ways under heaven, and no two minds in sages. The great Dao is inherently indescribable; if one reluctantly tries to describe it, it can only be said to be "empty, silent,emptiness, wonderful, tranquil, profound, and still". The vastness of the mind is also inherently beyond metaphor; if one reluctantly seeks a metaphor, it can only be characterized as "pure, quiet, spiritual, bright, harmonious, and gentle".

Second, the book notes that alchemical texts have always used many obscure terms, but scholars should be aware that such terminologies are merely metaphors. Terms like "yellow sprout" (huangya), "white snow" (baixue), "divine water" (shenshui), "flower pond" (huachi), "lead essence" (qianjing), and "mercury marrow" (gongsui) do not refer to actual substances existing in the body.

The second part, Bian Huo Lun (Treatise on Discerning Delusions), recounts the author’s nine-year practice under his master Chen Niwan. It contains many descriptions of successful alchemy, which appear quite mysterious—for example, "the yang spirit manifests its form, coming and going freely". Such descriptions of religious experiences are naturally difficult for ordinary people to understand, and the general public need not pursue them.

In fact, the most important part of Bian Huo Lun is the author’s exhortations on the mnemonic "forgetting scheming and eliminating worries" (wangji juelü). The author also points out that although many people in the world study immortality, few succeed. As a result, they often become doubtful and lose faith, or act rashly without guidance—both of which should be avoided.