Kuniyoshi (粟田口国吉) is traditionally regarded as a son of Norikuni and a member of the school of Yamashiro Province, where he held the court title of Saemon-no-jo. Among the craftsmen said to have been either his son or his student is Toshiro Yoshimitsu, one of the supreme masters of the form, and he is also recorded as having had a younger brother, Kunimitsu. Kuniyoshi's period of activity is established by a surviving work dated Koan 3 (1280) and by dated inscriptions in old transmission documents containing sword drawings — Kenji 4 (1278), Koan 6 (1283), and Koan 10 (1287) — placing him squarely in the mid- period. Among his extant signed works, are exceedingly few — only two with reliably authentic signatures are known — while are comparatively more numerous, and several also survive. In addition, there exists a celebrated ohira-zukuri known by the sobriquet "" (Crying Fox). A noteworthy point regarding Kuniyoshi's is the remarkable diversity of their shapes: some are squat and compact in a hocho-like configuration, some slender yet elongated, and others both broad and extended, displaying considerable variety in curvature as well — a characteristic inherited by his student Yoshimitsu.
Kuniyoshi's consists of finely forged mixed with , minutely worked with abundant (地沸) adhering like dust to produce a refined -like texture of exceptional beauty. The consistently observes that "the and are stronger than those seen in works" — a degree of assertiveness in that sets apart from its Yamashiro peers. His is characteristically a (中直刃) mixed with , , and small , with well adhering and fine (金筋) and running through. The defining hallmark, however, is the conspicuous appearance of (二重刃) running along the hardened edge, sometimes deepening into sanjuba. The historical treatise Kaifunki is quoted repeatedly across designations: "As a habitual trait, there is often , and it is also common for silver-like floating to appear in the ." The is invariably described as "bright and clear" (), and stands out in the ground steel. His typically runs straight, turning back in with a slight return, often showing overlays.
Across the designation record, Kuniyoshi's works are praised for an "elevated and dignified character" and a "remarkably high sense of dignity" — language the reserves for smiths of the first rank. His blades are repeatedly described as (健全) — sound and well-preserved — a condition that amplifies their aesthetic power. The intermittent from base toward tip is singled out as possessing "a distinctive charm characteristic of this smith," while the refined -like forging and beautifully gleaming edge- are cited as hallmarks that "fully display the virtues of work." The Kokon Meizukushi offers further praise: "In the color of the there is a gleam in the depths, like silver upon a tenmoku tea bowl dusted with ash." Kuniyoshi stands as the pivotal figure linking the elder masters to the brilliance of Yoshimitsu, and his works — whether signed of extreme rarity or the richly varied — represent the Yamashiro tradition at its most refined and technically assured.