Myōan Eisai 明庵榮西 (also read Yōsai; 1141–1215) — Late-Heian / early-Kamakura Japanese monk and the founder of the Japanese Rinzai-Zen 臨濟宗 tradition. Lay name Kaya 賀陽 (his father was a Shintō kannushi); style-name Myōan 明庵; sobriquet Yōjōbō 葉上房; posthumous titles Senkō Zenji 千光禪師 and Senkō Soshi 千光祖師. Born in Kibitsu (modern Okayama, Bicchū province) in 1141; died 1215, age 75.
Trained at Mount Hiei 比叡山 in the Tendai 天台 顯密 二教 (Exoteric-Esoteric) tradition, where he became a master of Taimitsu 台密 (Tendai Esoteric Buddhism) and was founder of the Yōjōryū 葉上流 sub-lineage. Travelled to Sòng-dynasty China twice: first in Qiándào 4 乾道四年 = 1168 (a brief study-visit) and again in Chúnxī 14 淳熙十四年 = 1187, when he stayed for several years, met the Línjì 臨濟 master 虛庵懷敞 Xū’ān Huáichǎng at Wànniánsì 萬年寺 on Tiāntái Mountain, and received Línjì-school transmission. When 懷敞 moved to Tiāntóngshān 天童山, Eisai followed; on his eventual return to Japan he supplied great timbers from the Japanese forests for the reconstruction of the Tiāntóng cloister.
Returned to Japan in 1191. Established Shōfuku-ji 聖福寺 at Hakata as the first Japanese Rinzai temple, and in 1202, with the patronage of the Kamakura shōgunate, founded Kennin-ji 建仁寺 in Kyoto — the central temple of the Rinzai-shū Kennin-ji-ha 臨濟宗建仁寺派. His Kissa yōjō-ki 喫茶養生記 (“Notes on Drinking Tea for Health”), composed 1211, is the foundational text of the Japanese tea-tradition.
His principal surviving Esoteric (Taimitsu) canonical work is the Jīngāngdǐng zōng pútíxīn lùn kǒujué 金剛頂宗菩提心論口決 (KR6o0074, T70n2293), a one-fascicle oral-transmission record on the Bodhicitta-utpāda Treatise KR6o0070 composed during his Tendai-Esoteric period before his definitive turn to Rinzai-Zen — an important documentary witness to his pre-Sōng formation.
DILA Buddhist Person Authority A001624.
Source: DILA A001624; standard Japanese Zen and Tendai biographical sources; Heinrich Dumoulin, Zen Buddhism: A History, vol. 2: Japan, Bloomington: World Wisdom, 2005, pp. 14–28.