Lit. "Dragon King Zennyo." The subject of a painting by one of the disciples of *Kūkai 空海 (774-835) which latter was the founder of the Shingon 真言 sect of Buddhism. In 824 Kūkai prayed for rain at Shinsen'en 神泉苑 in the Imperial Palace Kyoto as a result of which Zennyo ryūō is said to have appeared on Mt. Atago 愛宕 and caused it to rain. In a painting of the same event made by Jōchi 定智 (act. mid-12th century) housed in Kongōbuji 金剛峯寺 on Mt. Kōya 高野, Wakayama Prefecture, the deity appears in the guise of a Tang official riding a cloud. He holds a tray with a jewel in his left hand and has a snake's tail showing behind his robes. Images of him are likely to have been used in prayers for rain, and such prayers were addressed to him at Shinsen'en in later times.