Zhào Yǔyán 趙與虤 (the rare character 虤 reads yán, Jíyùn 牛閑切, glossed in the Shuōwén as “the snarl of two tigers” — hence his zì Wēibó 威伯, “Eldest of Awe”) was a member of the Sòng imperial clan, a tenth-generation descendant of Sòng Tàizǔ 太祖 by the “與” generation-character recorded in the Sòngshǐ Zōngshì biǎo 宋史宗室表. His native place and offices, if any, are not preserved. CBDB lists him under id 535194 without dates. His one surviving work, the Yúshūtáng shīhuà 娯書堂詩話 KR4i0038, cites with familiarity the late writings of Lù Yóu 陸游, Yáng Wànlǐ 楊萬里, and Lóu Yuè 樓鑰, and quotes Zhāng Hào’s 張淏 Yúngǔ zájì 雲谷雜記 (preface 1219); the Sìkù tíyào concludes that he must have been active under Sòng Níngzōng 寧宗 (r. 1194–1224) or after. The conventional floruit of 1231 (catalog meta) is consistent with these clues. His critical taste tilts toward shényùntuōsǎ 神韻脱灑 (spirit-resonance and unrestrained ease) and against the Jiāngxī school, citing approvingly the prefaces in which Yáng Wànlǐ and Jiāng Kuí distance themselves from the Huáng Tíngjiān 黃庭堅 manner — a position typical of the late Sòng jiānghú milieu in the years just before the SòngYuán transition.