Early- to mid-ninth-century Daoist fù-poet and inner-alchemy commentator, zì Dàxìn 大信, hào Tiānshuǐ yìrén 天水逸人 (“the Recluse of Tiānshuǐ”). His sole surviving work is the [[KR5a0263|Gǔshén fù 谷神賦]] (DZ 262), a short alchemical fù with the author’s own seven-character glosses. The signature on the title-page reads “天水逸人大信註” — “annotated by the Recluse of Tiānshuǐ, [styled] Dàxìn” — Tiānshuǐ 天水 being the commandery of present-day Gānsù, suggesting a Northwest origin. The catalog meta gives “9th cent 初期” as his floruit; the work itself shows Táng-period Daoist philosophical and alchemical idiom but no clear date or biographical detail. The title 《谷神篇》 also names a Yuán-period text by Lín Yuán (DZ 252), but the two are unrelated. No CBDB record found; the homonym 趙德 (Zhào Dé) of the Hán Yù circle (a Korean-born scholar at Cháozhōu, fl. 819) is a different person and unrelated to the Daoist author.