Late-Sòng paleographer, zì Zhòngdá 仲達, of Yǒngjiā 永嘉 (modern Wenzhou, Zhejiang). Granted jìnshì status in the Chúnyòu era (1241–52). Held offices including Guózǐjiàn bù, Prefect of Tāizhōu, Mìshū láng, and was promoted to Jūnqì shǎojiān in early Déyòu (1275) but pleaded ill and refused to come; his career thereafter cannot be traced. His sole surviving work is the Liùshū gù KR1j0034 in 33 juàn — the most radical Sòng-period departure from the Shuōwén radical tradition: Dài abandons the 540-radical scheme entirely in favor of a nine-fold thematic taxonomy (shù, tiānwén, dìlǐ, rén, dòngwù, zhíwù, gōngshì, zá, yí). His jiǎjiè doctrine — restricting the term to purely phonological borrowings — refines the canonical liùshū. CBDB carries no firm lifedates; the catalog meta gives “fl. 1252–1275” based on his documented official career.