Jakushitsu Genkō 寂室元光 (Shōō 3 → 1290; Jōji 6 / Shōhei 22 / 1367-09-03 (= 1367-10-04 NS)), Late-Kamakura → Nanbokuchō Japanese Rinzai-Zen master, founder (開山) of Eigen-ji 永源寺 at Mount Zuiseki-zan 瑞石山 in Ōmi 近江 (modern Higashi-Ōmi, Shiga), the head temple of the present-day Eigen-ji-ha 永源寺派 sub-school. Style-name (字) Jakushitsu 寂室; dharma-name Genkō 元光. Multiple posthumous titles culminating in Engai Hōzan Kokushi 圓鑑大師 / En’ō Zenji 圓應禪師. Native of Mimasaka 美作 province (modern Okayama).
Tonsured under Yakuō Tokken 約翁徳儉; received Yakuō’s transmission. Travelled to Yuán China in Genkō 1 / 1320 with his older dharma-brother Mukyoku Shigen 無極志玄, settling at Tiānmùshān 天目山 under Zhōngfēng Míngběn 明本 (1263–1323). Míngběn certified him with the Yánshì jiābǎo 巖室家寶 (“treasure of the cliff-room”) inscription, the source of his dharma-name. Returned to Japan in Karyaku 1 / 1326.
For the next forty years he refused all major appointments — declining the abbacy of Tenryū-ji and other Five-Mountain temples — and lived in successive mountain hermitages in Iyo, Bingo, and finally Ōmi. In Bunna 1 / 1352, at age 63, he accepted the foundation of Eigen-ji from Sasaki Ujiyori 佐々木氏頼 (1326–1370), the shugo of Ōmi. Died at Eigen-ji in 1367 aged 78. The Eigen-ji-ha is one of the fourteen present-day Rinzai sub-schools and the principal Japanese channel for Zhōngfēng Míngběn’s Mid-Phoenix Chan.