Yìcāo 義操 (fl. early 9th c., active under emperors Shùn-zōng 順宗 / Xiàn-zōng 憲宗 / Mù-zōng 穆宗 = ca. 805–824) — Tang Esoteric master of the Qīng-lóng-sì 青龍寺 East-Pagoda Cloister (青龍寺東塔院) at Cháng-ān; direct disciple of Huì-guǒ 惠果 (746–805) and a major node in the Tang Esoteric lineage that transmitted both the Garbhadhātu and Vajradhātu abhiṣeka into the second Tang Esoteric generation. Lifedates and native place unknown. He was conferred the title of State Preceptor (guóshī 國師) under three reigns.
He received the dual-mandala Garbhadhātu (胎藏界) and Vajradhātu (金剛界) transmissions from Huìguǒ at the same imperial Esoteric establishment where Kūkai had received them slightly earlier. Among his transmitted disciples were Hǎiyún 海雲, Fǎrùn 法潤, Yìzhēn 義真, Shēndá 深達, Dàyù 大遇, Wénfàn 文范, and most consequentially Fǎquán 法全 (法全), the master who taught Ennin (圓仁), Enchin (圓珍), and Shūei 宗叡.
His extant works include the Liǎngbù jīngāng míngháo 兩部金剛名號 (a 2-fascicle directory of the names of the dual-mandala Vajra deities) and the Tāizàng jīngāng jiàofǎ míngháo 胎藏金剛教法名號 (KR6j0023, T18n0864B).
Source: DILA Buddhist Person Authority A001477; Sòng Gāosēngzhuàn 宋高僧傳 (T50n2061) entries on the Tang Esoteric lineage; Ono Genmyō, standard Japanese-Esoteric biographical compendia.