(古宇多) names the founding stratum of the Uda school, the work that does not descend later than the period and so stands before the long continuation that the studio names would carry. The place the origin in Yamato: around the Bunpo era at the close of , the monk-smith Ko-nyudo Kunimitsu left Uda District in Yamato and settled at Utsu in , and from him the lineage took root. His sons Kunifusa and Kunimune are recorded, and across the and Jubi explanations the active founding hands are listed together as Kunifusa, Kunimune, and Kunitsugu, the generations that worked through the period before the name-bearing successions ran down into late . A signed Ko-nyudo Kunimitsu is hard to fix among several smiths who used the name; the Tokuju is read as the founder precisely because it shows the most archaic character of the surviving examples, earlier even than the Kunifusa pieces taken for .
The early steel is the school read at its source. The forging is mixed with and running that tends to stand (), adhering with , and over it a whitish or, on the founder's own work, a ; the carries a blackish, golden-toned cast that the explanations call a northern-province feeling. The temper sits in narrow to , opening into , , , and , with and and well set; along the the Yamato signature of and appears, while and run through. Against the later Uda generations, the face is the purer one. The Tokuju founder is appraised as workmanship entirely like Yamato; the Hie Shrine and Kurokawa by the Kunifusa hold a tight, clear and a bright forging, and the in the best stands strong and rounded where the later hands run coarser and more provincial. A lean exists, traced to the study of Norishige and Go, yet in this phase the steel and keep returning the blade to Yamato roots rather than dissolving into them.
To a blade is to catch the standing, whitish with its tendency and beneath a that might otherwise recall Yamashiro, and to bring a -rich, -laden example home from by the dark steel and the subdued () . The named early hands recur across the corpus: the Kunifusa, fixed against dated pieces no earlier than Koo 1 (1389) and the calligraphy of the lattice-broken 国; the signed Kunimitsu and Tomonori of around Meitoku; and the rare Tomoshige and Tomonori, smiths of few survivals through whom the phase's reach is gauged. Because signed early work is uncommon, the phase leans on attributions read off forging and temper, several entered as Ko-nyudo Kunimitsu. Provenance settles into shrine and institutional holding, the Hie Shrine and Kurokawa Institute serving as the calibrating standards against which other early Kunifusa are judged, and the dated examples valued as documentary footing for the study of how Yamato workmanship took its northern form.