The Golden Elixir

① The “functions” (yong 用) of Qian ☰ and Kun ☷ in the postcelestial domain (houtian). They enable the precelestial True Yang of Qian and the precelestial True Yin of Kun (represented by the solid inner line of Kan and the broken inner line of Li, respectively) to operate within the cosmos.

Kan and Li are the two functions of Qian and Kun. 坎離者乾坤二用。

② Yin containing True Yang (Kan ☵) and Yang containing True Yin (Li ☲). True Yang and True Yin are represented by the solid and broken lines at the center of the two trigrams, respectively.

Li is Yin within Yang, Kan is Yang within Yin. 〔陽中陰：〕離。〔陰中陽：〕坎。

Kan is externally Yin and internally Yang. Its external Yin is the postcelestial Yin, and its internal Yang is the precelestial Yang. Li is externally Yang and internally Yin. Its external Yang is the postcelestial Yang, and its internal Yin is the precelestial Yin. 坎者，外陰而內陽，其外陰即後天之陰，內陽即先天之陽；離外陽而內陰，其外陽即後天之陽，內陰即先天之陰。

③ Yin and Yang.

Li is Yang, Kan is Yin. 〔陽：〕離。〔陰：〕坎。