Yìxuán 義玄
Founder of the Línjì 臨濟 school of Chán, the single most consequential line in the later development of East Asian Chán / Zen Buddhism. Native of Cáozhōu 曹州 (present-day Shāndōng), lay surname Xíng 邢. Exact birth year is not transmitted; death is firmly attested on the tenth day of the fourth lunar month of Xiántōng 咸通 7 = 1 June 866 (《宋高僧傳》 and 《景德傳燈錄》). The conventional birth range ca. 810–815 is a scholarly estimate.
Initially studied vinaya and doctrinal Buddhism; took his decisive turn under Huángbò Xīyùn 黃蘗希運 (d. ca. 850), a dharma-heir of the Hóngzhōu 洪州 line descending from Mǎzǔ Dàoyī 馬祖道一. After further study under Gāo’ān Dàyú 高安大愚 and contact with Guīshān Língyòu 溈山靈祐, he settled in Xuānzōng’s Dàzhōng 8 (854) at the Línjì Yuàn 臨濟院 in Zhènzhōu 鎮州 (Héběi). There he taught with the characteristic apparatus later codified in his recorded sayings — the sānxuán sānyào 三玄三要, the sìliàojiǎn 四料簡, the sìbīnzhǔ 四賓主, and the celebrated use of the shout (hē 喝). Received the posthumous title Huìzhào chánshī 慧照禪師.
His lineage fanned out through heirs including Sānshèng Huìrán 三聖慧然 (慧然), Xīnghuà Cúnjiǎng 興化存獎, Guànxī Zhìxián 灌谿志閑, and Tánkōng Héshàng 譚空和尚 — twenty-two recorded dharma-heirs in all. The Línjì line eclipsed the other major Táng Chán houses by the Sòng and supplied the dominant doctrinal and rhetorical idiom of later Chinese Chán, Korean Sŏn, and Japanese Rinzai. His recorded sayings, the Línjì lù (KR6q0053), are attributed to the compilation of his disciple Huìrán but are transmitted in the Northern-Sòng 1120 recension of Yuánjué Zōngyǎn 圓覺宗演.