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, styled Yuanduzi, was a native of Poyang in Jiangxi (he claimed descent from the Song imperial house) and a celebrated scientist and Daoist priest of the Yuan. He lived in seclusion on Jiming Mountain at Longyou in Zhejiang, was the teacher of Chen Zhixu, and is regarded as the intermediary through whom the Quanzhen alchemy of the Northern Lineage was transmitted to the south. Zhao Youqin's best-known achievement is the Gexiang xinshu (New Book on Revising the Celestial Images), an astronomical and calendrical work in five juan which treats the principles of solar and lunar eclipses, the changing phases of the moon, observation of the fixed stars, the calculation of pi, and the experiment of "light and shadow through a small crack" (pinhole imaging); it is an important document in the history of Chinese optics and astronomy, and was abridged and edited by Wang Yi, a later follower of Zhu Xi, as the Chongxiu gexiang xinshu (Revised New Book on Revising the Celestial Images). His Daoist writings include the Xianfo tongyuan (Immortals and Buddhas of a Common Origin) and the Jindan wennan (Questions and Difficulties on the Golden Elixir), mostly lost; his life is recorded in Chen Zhixu's Jindan dayao (Great Essentials of the Golden Elixir), and his writings are listed in the General Catalogue of the Complete Library of the Four Treasuries and in Qian Daxin's Supplement to the Bibliographical Treatise of the Yuanshi.

Contributions & Influence

• Wrote the Gexiang xinshu and conducted a pinhole-imaging experiment, a celebrated work in the history of science
• Transmitted alchemical method 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 seclusion cultivating the Dao, representative of the loyalist Daoist priests 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)