Keisei (1189 - November 18, 1268) was a Buddhist priest in the Kamakura period. His go (pen name) was Shogetsubo (Chinese character was either 証月坊,松月坊, 勝月坊 or 照月坊). According to the Inokuma book (the Inokuma original copy) of 'Hirasan Kojin Reitaku,' he was an elder brother of FUJIWARA no Michiie.
He became a priest of the Jimon school of the Tendai sect and started to live in seclusion at Kyoto Nishiyama in 1208. He went to Sung (dynasty) (China) in 1217, returned to Japan in 1218 and founded Hokkesan-ji Temple at Nishiyama in 1226. He was acquainted with Koben (Myoe). He wrote 'Hirasan Kojin Reitaku,' 'Hokkesan-ji Engi,' and 'Hyoto Ryukyukokuki' etc. and 'Kankyo no Tomo' is also said to have been written by him.
His waka poems were selected in chokusen wakashu (anthologies of poems collected by Imperial command) starting when 'Shokukokin Wakashu' (Collection of Ancient and Modern Japanese Poetry, Continued) was compiled and onwards.