Lǐ Huáng 李潢
Style name Yúnmén 雲門, sobriquet Hòuzhāi 後齋. Native of Zhōngxiáng 鍾祥 (Húběi). Jìnshì of Qiánlóng 36 (1771), rose through the Hànlín Academy and held the offices of Zuǒyòu shìláng of the Boards of Works and of Revenue, and ultimately Gōngbù shàngshū 工部尚書 (President of the Board of Works). Death year 1811 confirmed by CBDB (id 59341); the birth year is not securely fixed but his jìnshì of 1771 places him as an active scholar from at least the 1760s.
The leading philological-mathematical commentator of the Qián-Jiā-period evidential-scholarship (kǎozhèng) tradition. Although his official career was at the apex of the Qīng bureaucracy, his scholarly identity was that of a working mathematician engaged in the recovery and exposition of the Suànjīng shíshū 算經十書. His three principal mathematical-philological projects, all completed in the closing decade of his life:
(1) The Jiǔzhāng suànshù xìcǎo túshuō 九章算術細草圖說 (KR3fc002) in 11 juàn — a complete detailed-procedure-and-diagrammatic exposition of the Jiǔzhāng suànshù, problem by problem and procedure by procedure. The work was incomplete at Lǐ’s death in 1811 and was put through final editing and publication by his student 沈欽裴 Shěn Qīnpéi.
(2) The Hǎidǎo suànjīng xìcǎo túshuō 海島算經細草圖說 (KR3fc003) in 2 juàn — the parallel exposition of 劉徽 Liú Huī’s Hǎidǎo suànjīng by detailed-procedure and diagram.
(3) The Jígǔ suànjīng kǎozhù 緝古算經考注 (KR3fc005) in 4 juàn — likewise the parallel exposition of 王孝通 Wáng Xiàotōng’s Táng cubic-equation treatise, edited posthumously by 沈欽裴.
The triple project — covering the Jiǔzhāng, the Hǎidǎo, and the Jígǔ — represents the most systematic late-imperial Chinese effort at recovering the procedural specifics of the medieval Suànjīng shíshū mathematical curriculum. Lǐ Huáng’s methodology, characteristic of high QiánJiā kǎozhèng practice, was to identify and reconstruct every implicit step of each ancient procedure, supplying the geometric diagrams required for understanding the area-and-volume decompositions, and emending the received text only where the implicit logic demonstrated corruption. He combined deep classical philological learning with genuine mathematical competence, and his expositions remained the standard scholarly references on these texts down to the mid-20th century.