Yasumitsu I was one of the foremost smiths active in Osafune of Bizen Province during the Oei era (1394-1428), and together with Morimitsu and Moromitsu he has been venerated as one of the "Three Mitsu" of Bizen at the time. Bizen swords of the early Muromachi period emulate those of the early to middle Kamakura period, with slender tachi having a koshi-zori curve and somewhat straightening towards the kissaki. The daggers are frequently, like this piece, straight or of slight uchi-zori curve. Irrespective of whether the hamon is choji, gunome, or suguha as on this blade, there is invariably a straight bo-utsuri, usually straighter than that of the Aoe school of the Nanbokucho period. The sayagaki states that this blade is by the second generation, probably considering an earlier smith active in the Enbu era (1356-61) as the first, although there is no known relationship between the two. The sayagaki mentions a daughter of Kuroda Chikuzen no Kami, who was an official (ogoromogata) to Lord Chuon of the Seikoin, and that according to a register of family swords the blade was once in the possession of a certain Shinjuin Dono. It was presented to one Takeuchi Hachiroemon.