The Golden Elixir

① With huandan 還丹 “reverted elixir”, one of the main designations of the Elixir in Neidan.

If you study immortality, you should study celestial immortality: only the Golden Elixir is the highest principle. 學仙須是學天仙，惟有金丹最的端。

The scriptures of the Immortals, ten thousand scrolls, all tell one thing: only the Golden Elixir is the ancestor, the root. 萬卷仙經語總同，金丹只此是根宗。

② Unity.

The Golden Elixir is the Great Ultimate (taiji). … All discourses about refining the Golden Elixir are teachings about the Great Ultimate. 夫金丹者，太極也。… 所謂煅煉金丹之說，即完成太極之旨。

③ The precelestial Breath (yuanqi).

The Golden Elixir is the precelestial Breath. 金丹乃先天之氣。

[The Precelestial Breath] is also called Golden Elixir. 〔先天之氣〕又名金丹。

④ Inner Nature (xing).

The original True Nature is called Golden Elixir. 本來真性喚金丹。

“Golden” means “solid” and “Elixir” means “round, complete.” … The original True Nature is indestructible for numberless eons, solid like gold and round like a pill. The more it is refined, the more it is luminous. 金者堅也，丹者圓也。… 本來真性，永劫不壞，如金之堅，如丹之圓，愈鍊愈明。

⑤ Conjunction of Nature (xing), Emotions (qing), Essence (jing), Breath (qi), and Spirit (shen). An image of the return to Unity.

When the three familiesThe five agents are arranged into three sets ("families") that share a numerical value of 5:

① The first set is made of Water (1) and Metal (4)
② The second set is made of Fire (2) and Wood (3)
③ The third set only consists of Soil (5)

The “five” are first reduced to “three” by reintegrating Wood into Fire and Metal into Water. The “three” are then reduced to “one” by conjoining Fire and Water through the mediation of Soil.

See this table for some of the main correspondences in Neidan. see one another, the Infant coalesces. 三家相見結嬰兒。 Comm. Liu Yiming: When the four images join one another, and when the five agents gather together, then Nature, Emotions, Essence, Breath, and Spirit all combine and become one thing. This is the Golden Elixir. 四象和合，五行攢簇，性情精氣神，都合而為一，是謂金丹。