The Wuchengzi 务成子

Wuchengzi, also known as "Wuchengzhao" or "Wucheng", is a legendary immortal before the rise of Taoism. He is said to have been a teacher of Yao and, according to another legend, also a teacher of Shun. Xunzi·Dalue (Xunzi·The Important Principles) states: "Shun studied under Wuchengzhao." It is said that he was an ancient expert in the art of sexual cultivation.

His health-preserving principle was to follow the laws of the changes of heaven, earth, yin, yang, and the four seasons to benefit physical health. Shiwen (Ten Questions), a medical book unearthed from Mawangdui, says: "Wucheng took the four seasons as auxiliary and heaven and earth as the classics." Hanshu·Yiwenzhi (Book of Han·Treatise on Arts and Literature) recorded Wuchengzi Yindao (Wuchengzi's Tao of Yin) in thirty-six volumes. Baopuzi Neipian·Mingben (Inner Chapters of Baopuzi·Clarifying the Origin) contains "Wuchengzi's Alchemy Method".