Tona (1289-April 17, 1372) was a Japanese monk and waka poet who lived in the final days of the Kamakura period and into the Northern and Southern Court period. He is thought to be the son of Mitsusada NIKAIDO, but another theory holds that he was the son of FUJIWARA no Morozane. His secular name was Sadamune NIKAIDO. Keiken, the monk and waka poet, was his son.
While still young, he resided on Mt. Hiei, where he studied Tendai teachings, and also studied at Mt. Koya thereafter. In his late twenties, he apprenticed himself to Shinkan of Kinren-ji Temple in Kyoto, thereby joining the Ji sect. Next he studied under Tameyo NIJO, and went on a walking tour of several different provinces in honor of his hero Saigyo, leading the lifestyle of a recluse by, among other things, building a thatched hut on the historic site where Saigyo had lived at Sorin-ji Temple in the Higashiyama area of Kyoto. He was a progenitor for the revival of the Nijo group (who had practiced the "way of waka") and while still in his twenties, he was counted among the Four Heavenly Kings of Waka, along with Keiun, Joben, and Kenko YOSHIDA. He was one of the few poets who was not a courtier, and his activities with poetry circles did not enter full swing until his final years. While the 'Shin-shui wakashu' (the New Collected Gleanings (of waka poetry)) was still in the middle of being compiled, its compiler, Tameaki NIJO, passed away, so Tona took over for him and completed the work; at the time he became compiler, he was 76. He came under the patronage and protection of the powerful Yoshimoto NIJO of the Northern Court (of Japan).
Literary works of his include the 'Sei-a sho' and the 'Gumon kenchu.'
The monk-poet Tona is not to be confused with the potter Tona ONO, who was another person entirely.