The published sources record that around the Bunpō era, at the end of the period, a monk-smith known as Ko-Nyūdō Kunimitsu came from Uda District in Yamato and settled at Utsu in , where he became the founder of the Uda school. No signed work securely by the founder is known. His earliest attributions are judged to him for their strong Yamato character, and a small dated Gen'ō 3 (1321) carries a red-lacquer attribution to Ko-Nyūdō. The name did not end with him. His sons Kunifusa and Kunimune carried the line into the period, and several later smiths took up the name Kunimitsu itself, the signature compendia recording it down through the Ōei, Kyōtoku and Meiō eras. The published sources therefore place each signed Kunimitsu with its generation by the , the temper and the hand of the signature.
The Yamato root is the first thing the published record names. Because the school came from Uda District, its works naturally carry a strong Yamato temperament, and Kunimitsu's show it plainly. On one signed an turns flowing toward the edge, and a frays into fine along the with touches of , while the runs straight with and barely turns back. On the attributed the temper is a or a , now and then with , and the ends in a small or sweeps off in . Of the Gen'ō , the writes that its large round, burned-off tells of a Yamato origin.
What sets these blades apart from Yamato work proper is the steel. On the finest attributed the published sources find a Yamato blade at first sight, but one whose carries a somewhat blackish tone that conveys a northern-province feeling. They add that the Uda character shows in the way the forms along the , and they call the piece an excellent work of restrained, subdued taste. A signed of the late or Ōei years is read the same way: its high reflects the home province of Yamato, while its darkened shows the flavour particular to the northern provinces. On a slender Ōei-era the steel is blackish within its golden tone and whitens where the grain stands, and the commentary names that dark cast, together with the rounded in the temper, as the clear mark of the Uda school. runs through more than half of his designated blades and through a third of them.
Beside the Yamato manner the published sources recognise a second range. The Uda smiths, they write, also worked in a -like manner, privately emulating Norishige and Gō, the earlier masters of . A signed Uda Kunimitsu in four characters, probably of the later period and placed roughly with the second generation, is forged in a fine, tight with fine . Its temper is a mixed with , with , and the enters in and turns back with a pointed tendency. Its explanation distinguishes two kinds of work: one with fine forging, fine and a bright steel colour, the other with a standing grain, large and a blackish steel. The holds that the former carries the current of Yoshihiro and the latter that of Norishige. A long with a large two-character signature, judged not later than the period, has a strong and , with , and and here and there, yet the published sources still find its Yamato temperament prominent.
Within his school Kunimitsu is the origin rather than one name among many. The published record defines as the work of the late and smiths of the line, Kunifusa, Kunimune and Kunitsugu among them, and every account of the school begins with his move from Yamato. Even his later namesakes keep his manner. The Ōei-era is a small piece in a refined narrow , and its 光 character is cut in a distinctive hand also recorded in the Kōzan .
Nine blades under his name stand in the tier, and he has no , no National Treasures and no Important Cultural Properties. Six are signed or inscribed: the dated with its red-lacquer attribution and five blades signed Kunimitsu, among them the and of the later generations. The other three are attributed to Ko-Nyūdō Kunimitsu. The published record preserves no provenance or museum holding for these blades, so his standing rests on the work itself. A Kunimitsu blade at this level comes to market only from time to time, as a signed later-generation or an attributed founder's , and most of what survives is held rather than traded. The founder's own work remains among the rarer things a collector of the northern schools may encounter.