Zhào Yǐfū 趙以夫 (1189–1256), zì Yòngfǔ 用父, hào Xūzhāi 虛齋. Member of the Sòng imperial clan (zōngshì 宗室). Resident in Chánglè 長樂 (Fújiàn). CBDB id 14811.
Jìnshì of Jiādìng 10 (1217). Career under Lǐzōng included substantive central-government posts: Liǎngzhè yùnpàn 兩浙運判 (Liǎngzhè Fiscal Vice-Commissioner, 1236; promoted out of the post in same year to Zuǒsī 左司); Tóngzhī Shūmìyuàn shì 同知樞密院事 (Vice Bureau Director of the Bureau of Military Affairs, 1238); prefect of Jiànníng 建寧 (from 1241). Final position: Zīzhèngdiàn xuéshì 資政殿學士.
Documentary references: Sòngshǐ 239.13b; Fújiàn tōngzhì 149.48b; Xiánchún Línān zhì 50.10b; Liú Kèzhuāng 劉克莊’s Wénjí 142.10a–19b (containing the funerary inscription).
Within the Kanripo corpus he is the author of KR1a0051 Yì tōng 易通 (6 juan; originally a tetrad of Yì tōng + Huò wèn 或問 + Lèi lì 類例 + Tú xiàng 圖象 in 10 juan total per the Sòngzhì; only the 6-juan main text survives, prepared as imperial-court-presentation manuscript). Composed 1241–1246 in collaboration with Huáng Jì 黄績 of Pútián.
Methodologically Zhào Yǐfū is a late-Sòng Dàoxué yìlǐ synthesizer. His doctrinal contribution — the non-variation-within-variation (biàn yì zhī zhōng yǒu bù yì 變易之中有不易) reading articulated through the Hóngfàn’s zhēnhuǐ 貞悔 division — is methodologically clean and was widely cited in the YuánMíng Yì tradition.