Xiānyú Shū 鮮于樞 (1246–1302; CBDB id 30354), zì Bójī 伯機, self-styled Kùnxué mín 困學民 (whence his studio-name Kùnxué zhāi 困學齋), was a major Yuán calligrapher and bǐjì-writer of Yúyáng 漁陽 (modern Tiānjīn). He served as Tàichángsì diǎnbù 太常寺典簿 under the Yuán. The Shū shǐ huì yào records him as “jiǔhān àofàng yín shī zuò zì, qí tài héngshēng” (when drunk, [his manner is] free-and-bold; reciting poetry and brushing characters, his strange forms come forth horizontally) — Zhào Mèngfǔ 趙孟頫 greatly respected him. His one surviving work is the Kùnxué zhāi zá lù 困學齋雜錄 (KR3j0135) in 1 juàn, a suí bǐ zhá lù (casual bǐjì-notes) on shī huà and miscellany. Lì È 厲鶚’s bá (postface) notes that the book preserves Jīn-dynasty poetry that supplements Liú Qí’s Guī qián zhì.