Osafune Sanenaga
真長 (Sanenaga)
An Osafune smith in Bizen of the second half of the Kamakura period (around 1278-1306), of the school's first period.
Profile
Sanenaga worked at Osafune between the Kōan and Kagen eras (1278-1306), according to Kotobank. The sources do not agree on his master: Kotobank makes him the son or pupil of Mitsutada, the founder of Osafune, and the Japanese Wikipedia places him among the sons or pupils of Nagamitsu, with Kagemitsu and Chikakage, among others. The same Wikipedia names him with Chikakage among the known masters of the school.
He signed «Sanenaga» with two characters or with a long signature giving the province and the village of Osafune. The Kotō Taikan reproduces one blade by him. No works of his with an official designation are known in the sources consulted.