At Ukan-no-shō in Province, a place name later written Ukai, a small group of smiths worked from the close of the period into the first decades of , every one of them setting the character , the cloud, at the head of his name; for that habit the published sources know them equally as the Ukai school and as the Unrui, the cloud group. Unshō is named the line's de facto founder, his years fixed around Kengen and Kagen (1302 to 1306) through the dated blades of his son Unji, who alone among the early hands left work inscribed with eras, the Shōwa, Bunpō and Kenmu nengō; Unju, read also Unshige, carries the line a third remove into the mid-, his dated Jōji of 1368 set against the founders before him. Tradition holds that Unshō and Unji went up to the capital, learned forging from the Yamashiro smiths, and served Retired Emperor Go-Daigo as duty smiths, and the rare blades with a sixteen-petal chrysanthemum crest below the lend that account its weight. The make that resulted stands apart from the mainstream: within an essentially body the members describe a Yamashiro cast intermingled, with no small influence from the school of neighboring besides, so that the published sources call the line a distinctive presence among works.
The shared vocabulary begins with the curvature: a slender with at the base and a small point, arching evenly in a high wa-zori where the work of the generation runs , the papers reading that even arch as close to Kyoto work. Against the of the mainline the Ukai hands temper , narrow to medium, mixed with , , shallow and a small , the and entering thickly and slanting in reverse in the manner; , and work along the edge, and the now tightens under , now sinks subdued. The is mixed with , knit to on the finer blades, with , fine and a steel color tending blackish, across which stands a ; the group's own signature is what the papers call the black peculiar to the Unrui, as if pressed in with the pad of a finger. The turns back round, , and the round turn that does not point is held the school's particularity even where the make breathes . Within that common ground the members divide by temper: Unshō's is mostly low and quiet in its activity; Unji is the hand, his line wider and strongly -laden with and standing out, his flowing and at times masa-tinged; Unju presses the idiom toward the with deepening and a scantier , his most Yamato-leaning blades running almost into with and a sweep.
To Ukai work is to read the line as the closest to Kyoto work among products: the wa-zori and even arch, the dark , the laced with , and the round that settles a blade which might at first sight be confounded with the school or with neighboring . The judges separate the hands by the activity of the , and stronger carrying an unsigned blade to Unji rather than Unshō, the reverse-chisel strokes of the and the date cut straight beneath a long signature answering to practice on Unju's signed pieces. Among the members Unji is the name a collector is likeliest to meet and the chronological anchor of the whole group, Unshō the founder whose stronger blades approach his successor, Unju the rare and individual third hand. What survives privately is most often an attributed on the silhouette and the cloud-group traits, or, far less often, a signed ; provenance runs through the Uesugi hand-picked thirty-five, the Mōri, Ikeda, Maeda and Date houses and the Imperial Family, while the patrimonial pieces and museum holdings do not move.