Keiken (year of his birth and death is not clear) was a Buddhist monk cum waka poet in the period of the Northern and Southern Courts (Japan). He belonged to Nikaido clan, a samurai family. His father was Tona, a Buddhist monk cum waka poet. Gyojin, a monk cum waka poet, was his son.
In 1364, he assisted his father Tona in selecting waka poems to be compiled in Shin-shui Wakashu (New shui anthology of Japanese poetry). Also, he often participated in uta-awase (waka poetry competition) such as Nenchu-gyoji Uta-awase and Shintamatsushimasha Uta-awase. After the death of his father, he inherited a villa called Saike-en as well as Joko-in, both were located in Ninna-ji Temple, and later he was appointed to Hoin (the highest rank in the hierarchy of Buddhist priests) and Daisozu (the highest grade that can be held by one who has reached the second highest rank in the hierarchy of Buddhist priests).
His waka poems were selected in chokusen wakashu (the anthology of Japanese poetry compiled by the Imperial order) such as Shinshoku Kokin Wakashu (New Collection of Ancient and Modern Japanese Poetry Continued).