Cáo Duān 曹端 (1376–1434), zì Zhèngfū 正夫, hào Yuèchuān 月川, was a native of Miǎnchí 澠池 (Hénán) and the foremost early Míng Zhūzǐ xué 朱子學 classicist. Jǔrén of Yǒnglè wùzǐ 戊子 (1408); appointed Xuézhèng 學正 of Huòzhōu 霍州 (Shānxī), later transferred to Pǔzhōu 蒲州. His official biography is Míng shǐ j. 282 (Rúlín zhuàn). The Míng shǐ records that “his learning made it its business to embody and practise; the holding-still in quiet (jìng cún 靜存) was its essential”. His commentary on the Tàijí tú shuō (KR3a0023), Tōng shū (KR3a0025) and Xī míng (KR3a0024) is the foundational early-Míng integrated annotation of the three core Northern-Sòng daoxué texts; Lúo Qīnshùn 羅欽順 and Hú Jūrén 胡居仁 are his successors but not his contemporaries. The Míng shǐ remarks: “the upright Confucians of the Míng dynasty are best taken as Cáo Duān, Hú Jūrén and Xuē Xuān 薛瑄, with Duān opening the way for the other two.” His textual critique of the Zhūzǐ yǔlèi against the Tàijí tú shuō commentary — that the latter is from Zhū Xī’s hand while the former is the disciples’ record — is one of the earliest examples of intra-Zhūzǐxué textual stratification (the so-called biàn lì 辨戾, “distinguishing the discrepancies”). CBDB id 34498, dates 1376–1434.