Yú Rǔyán 兪汝言 (variant 俞汝言; 1614–1679), zì Yòují 右吉, hào Jiànchuān 漸川 (= “Gradual River”), was an early-Qīng evidential-school 考證 Chūnqiū scholar from Xiùshuǐ 秀水 (Jiāxīng 嘉興 prefecture, modern Zhèjiāng). Lifedates 1614–1679 from CBDB id 338399 (alternate id 56452 is undated); a mùbiǎo 墓表 (grave-tablet inscription) survives in Wèi Xǐ’s 魏禧 Wèi Shūzǐ wén jí 魏叔子文集 juǎn 18.
He never passed the higher examinations (he signs both his Chūnqiū prefaces simply as Jiànchuān zhūshēng 漸川諸生 — “registered student of Jiànchuān”) and lived as a private scholar through the MíngQīng transition. According to the Sìkù tíyào he went blind in his last years and dictated his work orally to assistants. He was a friend of Wèi Xǐ 魏禧 and circulated in the Sōnglíng 嵩齡 / Yíshān 易山 evidential-scholarship milieu of early-Qīng Zhèjiāng. Zhū Yízūn 朱彝尊 in Jīngyì kǎo 經義考 cites Miào Yǒng 繆泳’s notice characterising him as deeply versed in the Classics and the histories, particularly knowledgeable on Míng-dynasty institutions and compiler of a Zǎixiàng lièqīng niánbiǎo 宰相列卿年表 (table of grand councillors and high officers).
His two Chūnqiū works in the Sìkù, both completed in Kāngxī bǐngchén 丙辰 (1676), are: Chūnqiū píng yì 春秋平義 (KR1e0099) in 12 juǎn (the principal exposition, drawing eclectically on prior commentators while rejecting both the Sūn Fù 孫復 / Hú Ānguó 胡安國 (胡安國) “no-praise-only-blame” line and the late-Míng over-philological tendency); and Chūnqiū sìzhuàn jiūzhèng 春秋四傳糾正 (KR1e0098) in 1 juǎn (the appended summary, organising the errors of the four commentaries under six heuristic categories). Other works (a Hànchuān jí 漸川集 of poetry and prose) were not extant by the Qiánlóng compilers’ time. The diagnostic of his work — anchored in the famous formula in his Chūnqiū píng yì preface, chuán jīng zhī shī, bù zài qiǎn ér zài yú shēn, Chūnqiū wéi shèn 傳經之失，不在淺而在於深，春秋為甚 (“the failures of commentaries on the Classics lie not in superficiality but in over-deepness; the Chūnqiū is the worst case”) — is repeatedly quoted with approval in the Sìkù compilers’ notices on Qīng-period Chūnqiū studies, including the imperial Yù zuǎn Chūnqiū zhí jiě (KR1e0095).