Yú Liú 虞流 (fl. Northern Sòng), obstetrical compiler whose now-lost Bèichǎn jìyòng fāng 備產濟用方 is preserved substantively only within juǎn 6 of 朱端章 Zhū Duānzhāng’s Wèishēng jiābǎo chǎnkē bèiyào (KR3ei056, c. 1180). Together with 李師聖 Lǐ Shīshèng’s Chǎnyù bǎoqìng jí (KR3ei076), Yú’s work forms the substantive Northern-Sòng obstetrical-formulary core of Zhū Duānzhāng’s compilation. No independent transmission of Yú’s text survives; no biographical detail is recorded in standard sources. Not in CBDB.