Yasumitsu of in Province, together with Morimitsu, stands as one of the "twin pillars" among the smiths of the early period collectively termed Oei-. The first generation, who styled himself Uemon no Jo, was active around the Oei era (1394--1428); thereafter the name was successively inherited, with sword-signature compendia counting five generations bearing the name down to the end of the period, though "as to a strict generational division, there remains room for further examination." The second generation, known as Sakyo no , is associated with the so-called Eikyo- smiths active around the Eikyo and Bunan eras. The group's ideal "appears to have been a revival of the period," visible in shapes and in the deliberate re-creation of tempering that had fallen out of favor during the period; yet the school's own distinctive character is always discernible beneath this revivalist surface.
Within the Oei- manner, two principal modes are recognized: on the one hand, a brilliant -ba in which open, relaxed with is mixed with , forming "a splendid, large-patterned, flamboyant "; on the other, a calm of restrained, archaic tone. In both modes the school's identity is revealed in a forging of mixed with in which the grain stands out conspicuously, with dark lines resembling entering the and appearing. The characteristically incorporates with widely opened "hips," while the becomes pointed at the tip in the idiosyncratic manner "commonly called the 'candle-wick' (rosoku no )." A further point of connoisseurship for this group is the finishing of with rounded ends () above the . Yasumitsu's works are "encountered comparatively often" and reflect what the describes as "a high level of technical capability," producing an archaic () atmosphere in both and that can, at first glance, "call to mind the workmanship of the -period school or earlier traditions."
Across the full range of his production -- , , , , and the exceedingly rare omi- -- Yasumitsu is consistently praised for leaving behind "highly skilled works in every format." His finest pieces are described as possessing a that is "bright and clear," a of superior quality with an richness, and a condition that is -- sound and well-preserved. The repeatedly emphasizes that his works serve as "excellent material" for understanding both the breadth of his expressive range and the characteristics of the Oei- school at large. Whether in the commanding vigor of his large-pattern or in the quiet classical elegance of his , Yasumitsu's stature as a "representative master" of one of the most refined chapters in swordsmithing remains firmly established.