Keisen Sōryū 景川宗隆 (Ōei 32 → 1425; Meiō 9 / 1500-08-21), Mid-Muromachi Japanese Rinzai-Zen master, one of the four principal dharma-heirs (the Shihatsu 四派 “Four Branches”) of 宗深 Sekkō Sōshin (1408–1486) and founder (派祖) of the Ryūsen-ha 龍泉派 sub-lineage of Myōshin-ji 妙心寺. Style-name (字) Keisen 景川; dharma-name Sōryū 宗隆. Posthumous title Honnyo Jisshō Zenji 本如實性禪師, conferred by Emperor Go-Tsuchimikado 後土御門天皇. Native of Mino 美濃 province.
Tonsured young; received transmission from Sekkō Sōshin at Heibai-in 衡梅院; later founder of Kōun-ji 興雲寺 at Mount Dai-ryū-zan 大龍山 in Yamato 大和, and successively abbot of Daitoku-ji 大徳寺, Myōshin-ji 妙心寺 (twice — re-installed, saijū 再住), Zuisen-ji 瑞泉寺 in Owari 尾, and other major temples. The Ryūsen-ha line descending from him is one of the three present-day Myōshin-ji sub-lineages active in the Rinzai sect.