Zhao Youqin赵友钦

Style & Daoist names

courtesy name Zigong (one account: Jingfu), sobriquet Yuanduzi, Zhao Yuandu

Period

Late Song–early Yuan

Dates

c. 1271 — c. 1335

School

Quanzhen (Complete Perfection) Daoism, Southern Lineage of the Golden Elixir (Nanzong)

Role

Internal Alchemy MastersAstronomerMathematician

Birthplace

Poyang (present-day Poyang, Jiangxi; one account: a Song imperial clansman)

Life

Zhao Youqin, sobriquet Yuandu zi, was a native of Poyang, Jiangxi (he claimed descent from the Song imperial house), and a renowned scientist and Daoist of the Yuan dynasty. He lived in seclusion on Jiming Mountain in Longyou, Zhejiang, and was the teacher of Chen Zhixu, regarded as the intermediary through whom the Northern Lineage's Quanzhen alchemical methods were transmitted to the south. Zhao Youqin's most celebrated achievement is his five-chapter work on astronomy and calendrical calculation, the Gexiang xinshu (New Book of Reforming the Celestial Images), which discusses the principles of solar and lunar eclipses, changes in the phases of the moon, observation of fixed stars, calculation of the value of pi, and an experiment on "small-aperture light and shadow" (i.e. pinhole imaging) — an important document in the history of Chinese optics and astronomy, later abridged and revised by Wang Yi, a follower of Zhu Xi, as the Chongxiu gexiang xinshu (Revised New Book of Reforming the Celestial Images). His Daoist writings include the (mostly lost) Xianfo tongyuan (Immortals and Buddhas of the Same Origin) and Jindan wennan (Questions and Difficulties on the Golden Elixir); his life is recorded in Chen Zhixu's Jindan dayao and in the "Bibliographical Treatise" (Yiwen zhi) of the Yuan shi.

Contributions & Influence

• Wrote the Gexiang xinshu and conducted a pinhole-imaging experiment, a celebrated work in the history of science
• Transmitted alchemical methods to Chen Zhixu, serving as the intermediary in the convergence of the Southern and Northern Lineages
• As a claimed descendant of the Song imperial house, he lived in reclusion pursuing the Dao, representing the Daoist loyalists (yimin) of the Yuan

Works

• New Book on Revolving Celestial Images (Gexiang Xinshu)
• Immortals and Buddhas from the Same Source (lost)
• Questions and Answers on the Golden Elixir (lost)