On the side of the koiguchi are the traces of a museum accession number, B71 N:578.
There might have been two generations of Kanemitsu working in Osafune from the 1320s through the 1360s. Dr. Homma broke down the theoretical working dates of the two generations to circa 1325-1340 and 1340-1368. The first generation Kanemitsu is famous as one of the Ten Great Pupils of Masamune (Masamune Jutetsu) and was known to have made blades with Kagemitsu-style tempering, mainly kataochi-gonome, suguba or suguba with gonome. Son of Kagemitsu and grandson of Nagamitsu, he produced blades which reflected the political climate in which rival forces of the Northern and Southern Imperial Courts were fighting for control of the country. The majority of fighting was done on foot with greatly improved armor, and the practical demands of the battlefield required straighter, wider and heavier blades. An outstanding example of this type was included in the Compton Collection sale, Part I, lot 251.
Kanemitsu blades from the Kan-o (1350-1) to Embun (1356-60) eras during the brief Northern Dynasty (i.e., the Nambokucho period) fall into two general groups: one of typically Nambokucho width and with an elongated point (the above-mentioned lot in Part I) and one with a strong notare hamon. This example displays the kataochi gonome usually associated with the first generation Kanemitsu, but the Embun date would appear to eliminate him as the author of this blade. One Juyo bunkazai tachi (see Homma, Showa dai meito zufu, no. 229) with an Embun 1 date and given to Embun Kanemitsu, does display a strong, regular notare. Within the ten year period of 1350-60 there was apparently an intermingling of styles between the two smiths.