The Thirty-Six Immortals of Poetry are a group of Japanese poets of the Asuka, Nara, and Heian periods selected by Fujiwara no Kintō as exemplars of Japanese poetic ability. The oldest surviving collection of the 36 poets' works is Nishi Honganji Sanju-rokunin Kashu of 1113. Similar groups of Japanese poets include the Kamakura period Nyōbō Sanjūrokkasen (女房三十六歌仙), composed by court ladies exclusively, and the Chūko Sanjūrokkasen (中古三十六歌仙), or Thirty-Six Heian-era Immortals of Poetry, selected by Fujiwara no Norikane (1107–1165). This list superseded an older group called the Six Immortals of Poetry.

Ariwara no Narihira was a Japanese courtier and waka poet of the early Heian period. He was named one of both the Six Poetic Geniuses and the Thirty-Six Poetic Geniuses, and one of his poems was included in the Ogura Hyakunin Isshu collection. He is also known as Zai Go-Chūjō, Zai Go, Zai Chūjō or Mukashi-Otoko.