Northern-Sòng Yìxué writer of Jiāngnán, zì Yángtíng 揚庭. The principal target of 邵伯溫 Shào Bówēn’s Yìxué biànhuò (KR1a0017), where he is depicted as having stolen a manuscript copy of 邵雍 Shào Yōng’s xiāntiān 先天 numerological materials from the deathbed of 王天悅 Wáng Tiānyuè (one of Shào’s two student-confidants). On this purloined basis he is said to have composed Yì zhuàn 易傳, Yì cè 易測, Míng fàn 明範, Shíyòng shū 時用書, and Wǔjīng míng yòng shù shū 五經明用數書 — works recorded in the Sòngshǐ Yìwén zhì and the Shūlù jiětí but all now lost. 司馬光 Sīmǎ Guāng’s Jí preserves a memorial Jìn Zhèng Guài Yì cè zhāzǐ praising the Yì cè in markedly positive terms — evidence, on the Sìkù editors’ analysis, that Zhèng’s corpus comprised both a substantive yìlǐ commentary and a separate divinatory-numerological handbook.