Ān Zhǐzhāi 安止齋
A late-Yuán mathematical educator known only by the sobriquet Ān Zhǐzhāi (“Resting-Studio of Calm”); the given name is not preserved in the bibliographic record. Birth and death years unknown; conventionally dated fl. c. 1373 from the preface date of his work. Identity is uncertain — some MíngQīng sources refer to him as the same person as Hé Píngzǐ 何平子 (a contemporary mathematician), but this conflation is not securely established.
His sole surviving work is the Xiángmíng suànfǎ 詳明算法 (KR3fc014) in 2 juàn (the catalog records 4 juàn; some editions divide the text differently), one of the principal late-Yuán arithmetical primers. The work was repeatedly reprinted in the Míng and incorporated into the Korean Sǎn-hag-byeon-eun 算學便儒 (1660) and the Japanese Kuwabara Goken’s Sanpō Ittō 算法一統 — making it among the most widely transmitted Chinese mathematical works of the late-Yuán / early-Míng period.