Xú Dùyú 徐渡漁, late-Qīng physician of obscure biographical record. Author of KR3ep096 Xú Dùyú xiānshēng yīàn, a single-juǎn casebook with clinical signature placing him within the late-Qīng Wáng Mèng-yīng-school wēnbìng tradition. The use of the xiānshēng (Master) form in the title indicates posthumous compilation by disciples or family. Not in CBDB.