Liú Wánsù 劉完素 (zì Shǒuzhēn 守真, ca. 1110 – ca. 1200, 金), the founder of the JīnYuán “fire-and-heat school” (火熱派) and the first of the canonical JīnYuán “Four Masters” (金元四大家, with Zhāng Cóngzhèng 張從正, Lǐ Gǎo 李杲, and Zhū Zhènhēng 朱震亨). Native of Héjiān 河間 (modern Héběi); his epithet “Héjiān” became eponymous of his school. Biography in the Jīn shǐ Fāngjì zhuàn. Liú’s foundational doctrinal contribution is the systematic re-grounding of clinical practice in the Sùwèn’s “Zhì zhēn yào dà lùn” 至真要大論 — particularly the 19 disease-mechanism (病機十九條 bìngjī shíjiǔ tiáo) framework — and the development from there of the doctrine that “the six excesses (liù qì) all transform into fire” (六氣皆從火化), which made cold-cooling pharmacotherapy the principal therapeutic strategy. Major works in the SKQS / Kanripo: Sùwèn xuánjī yuánbìng shì 素問玄機原病式 (KR3e0047, 1 juan); Xuānmíng lùn fāng 宣明論方 (KR3e0048, 15 juan); other works circulating in the SòngYuánMíng print line. Liú’s school dominates JīnYuán northern Chinese medicine and is the immediate ancestor of Zhū Zhènhēng’s Yuán-period “yīn deficiency” school.