Lü Dongbin's The Secret of the Golden Flower excerpt describes the interplay between the primordial spirit (yuan shen), residing in the space between the eyebrows, and the cognitive spirit (shi shen), located in the heart. It emphasizes cultivating the primordial spirit to transcend earthly limitations and achieve immortality. This involves refining the "hun" (soul) and subduing the "po" (corporeal aspect) associated with the cognitive spirit, which is likened to a domineering ruler needing wise counsel. The text details practices, such as "returning the light," to achieve this spiritual transformation, ultimately forming a "sacred embryo" (sheng tai). The cultivation process involves balancing essence, spirit, and intention, three vital components in Daoist practice.