Chén Zhāng 陳章, late-Southern-Sòng disciple of 易祓 Yì Fú. His preface dated Shàodìng wùzǐ (1228) fourth month first day to Yì Fú’s Zhōuyì zǒng yì 周易總義 (KR1a0048) records that Yì Fú spent “more than twenty years” on the work after his initial jīngyán 經筵 (imperial-classroom) lectures on the Yì, and preserves Yì Fú’s signature cosmological-anthropological formulas about the Yì as controller of yuánqì 元氣 and the sage as its quánhéng 權衡. Also records the now-lost companion four-juan Yì xué jǔyú 易學舉隅.