Yáng Quán 楊泉 (life-dates unknown, fl. c. 265 – c. 300), zì Déyuān 德淵, a late-Sān-guó-Wú and Western-Jìn chùshì 處士 (private scholar in retreat). His native place is variously given in late sources as Kuàijī 會稽 (Zhèjiāng) or Liángguó 梁國 (Hénán). After the Jìn conquest of Wú in 280 he refused all Jìn office and retired to private study, devoting himself to writings on cosmology, astronomy, meteorology, calendrics, agriculture, medicine, and craft technology. His principal extant work is the Wùlǐ lùn 物理論 KR3j0198 (originally sixteen piān per Suíshū jīngjí zhì, lost and reconstructed in the Qīng by Sūn Xīngyǎn 孫星衍 in the Píngjīn guǎn cóngshū 平津館叢書); a separate Tàiyuán jīng 太元經 in the manner of Yáng Xióng 揚雄 was reconstructed by Mǎ Guóhàn 馬國翰. He is sometimes confused with the Sòng-dynasty homonym Yáng Quán 楊泉 of CBDB. As a thinker, Yáng Quán continues the line of Wáng Chōng 王充 in materialist qì-cosmology and is treated in Joseph Needham’s Science and Civilisation in China II.367–8 as a notable WèiJìn natural philosopher.