no Kami Kuniyasu, commonly called Genzaemon, signed his blades with a five-character and was the third son of the first-generation Kawachi no Kami Kunisuke of Osaka, the younger brother of the second generation whom the published sources call Naka-Kawachi. He worked in Settsu during the years of the early period, in the wing of the Osaka school. That line descends through Kunisuke from the Ishido tradition, which had revived the in new-sword steel, and Kuniyasu carries the manner one remove from its second-generation peak. The published record places him in skill just below his elder brother, observing that comparatively few of his works reach Naka-Kawachi in the quality of both and , while granting that the best of them approach him closely. On one the judges go further, finding the work so fully his own that it is 「中河内と選ぶところがない」, a piece that may be chosen without distinction from Naka-Kawachi.
What marks his hand first is the and the fist-headed clove set within it. Over a that opens the temper above the , the rises into a mixed with , and into the pattern Kuniyasu sets the , the clenched-fist heads that the second-generation Kunisuke had made the ornament of the line. On more than half his designated blades the judges name this feature as the point that exhibits his characteristic work, and on his richest the crests align further into and admit the large-tasselled o-busa-, the temper running tall with marked rises and falls. The straight at the base is the quiet tell that separates this from the old it otherwise recalls, an Osaka convention rather than a habit. enter the well, are sometimes mixed in, adhere, and through the pattern run and , the staying bright and clear.
The is a tight , closely forged and laid with , here and there opening into a patch of larger . On his finest work the gathers fine and thick with delicate , a forging the published sources call 「如何にも大阪新刀らしい」, thoroughly characteristic of Osaka , beautiful and clear. The and cut on one blade, and the double grooves on another, are the carving of a careful late hand. Over so animated an edge the stays restrained, running straight and turning back in a small rather than following the into the point, the calm finish the Osaka smiths favored. The is the - build, the slightly wide with little taper from base to tip, the somewhat thick, the shallow and the compact; one long extends past two six in a dignified and well-balanced whose thick gives a real sense of weight in the hand.
The corpus the published record preserves is small and remarkably consistent: seven designated , all but one signed, all on carrying the five-character no Kami Kuniyasu signature near the of the . There is no or problem to untangle and no dated survival to anchor a chronology, so the rests entirely on the work, and the work is of one settled manner seen at two settings. At the everyday setting the is regular and the intermittent; at the best, on the late Reiwa-designated pieces, the temper broadens, the kobushi heads cluster and align, and the judges reach for their fullest praise. The phrase they apply to his most worked blade is exact: it is a 「拳形丁子乱れを焼いた典型作」, a quintessential example of his work in which the fist-shaped is tempered above a placed at the base.
Within the Kawachi-no-kami line Kuniyasu is the chief hand carrying the manner alongside and just beneath his brother. The resemblance the judges draw is to Naka-Kawachi, again and again, and it is a true one, grounded in the shared , the dense and the bright the two brothers worked from the workshop. His own blades are told within that closeness by degree rather than by a different feature: where his temper holds its rises and falls and avoids the rigidity into which the fist-shaped can stiffen, the result gains a natural texture and a depth of taste, and on one the published sources find his technical level revealed in 「殊更に拳形丁子を交えた華やかな丁子乱れに国康の技術の高さ」, the high skill shown in the gorgeous with its fist-shaped heads. They call that blade a superior work that approaches Naka-Kawachi, 「中河内に迫る優品」.
In the connoisseurship he is a smith of the middle tiers rather than the summit, his record one of seven blades that have reached , none yet raised to and none standing in the higher designations above it. None of the seven carries a recorded provenance or a named former owner, so his blades are encountered for the quality of their workmanship rather than for the houses they passed through. That makes him an accessible point of entry into the Osaka manner: a signed, sound by Kuniyasu comes to the serious collector with some regularity, far more readily than the rare survivals of his father or the prized work of his brother Naka-Kawachi, and it offers the line's distinctive on a blade that the judges themselves at their warmest set beside the second generation. The published sources give his common name as 「源左衛門」 and fix his place as the third son of the first Kawachi no Kami Kunisuke; the seven on record carry that lineage in steel, a careful and at moments brilliant hand working the brightest of the early Osaka school.