His times
- The dates of his birth and death are not known (生没年不詳, seibotsunen fushō).
- The Tokyo National Museum dates his blades to the Kamakura and the Nanbokuchō, in the 14th century. The Japanese Wikipedia places him in the Nanbokuchō; the Nihon Jinmei Daijiten and the Britannica, at the end of the Kamakura. Without a signed or dated work, there is no way to decide.
His name
- He lived at Matsukura-gō, in the Niikawa district of Etchū, today Uozu, in Toyama. His nickname, Gō, is written 郷 (Gō) or 江 (Gō), and is explained by the 江川 (Gōgawa) river in the same district.
- Ogasawara Nobuo believes that 郷 (gō) is too common a place name and that the original is 江 (Gō), after the Ōe clan.
- The Britannica makes him a vassal of the Momoi, lords of Matsukura castle, fond of forging, who went to Kamakura to learn from Masamune.
What tradition says
- That he died at twenty-seven.
- That he was a pupil of Masamune or of Etchū Norishige, and one of the ten pupils of Masamune (Masamune jūtetsu). The old source that supports it is the Ōjakushō, of the mid-Muromachi, which records a sword signed 江 (Gō) and gives him as a pupil of Gorō Nyūdō, that is, of Masamune.
The esteem of Edo
- With Masamune and Awataguchi Yoshimitsu he forms the three greats (tenka sansaku), an expression of the Edo period.
- Nagasone Okisato, the first Kotetsu, took him as a model; Inoue Shinkai and Nanki Shigekuni also imitated him, and the NBTHK recalls that Shinkai held him to be the ideal smith.