For a comparable mei, see the Momoyama period illustrated handscroll Kotoku toezu shusui, vol. 1, no. 21.
Genzaemon Nobukuni (Nobukuni III) was a student of his older brother Shikibu Nobukuni (Nobukuni II, also Oei era [1394-1427]), who himself was a student of their father, Nobukuni (Nobukuni I). Nobukuni I was a student of Ryokai. The wide shape of this blade and the narrow suguba resemble an early Soshu style blade in the manner of Ryokai more than the more exuberant blades of Nobukuni I.