From the end of the period into the , the swordsmiths Unsho, Unji and Unshige worked at Ukan-no-sho in Province, a place name later also written Ukai. From their residence the line is called the Ukan or Ukai school; because every smith set the character , the cloud, at the head of his name, the published sources also know them as the Unrui. Unsho is named outright the school's "de facto founder" (事実上の祖). No dated work of his survives; the registers place the first generation around Kengen and Kagen (1302 to 1306), and his years are fixed through the dated blades of Unji in Showa, Bunpo and Kenmu. Tradition holds that he went up to the capital with Unji, learned forging from the Yamashiro smiths, and served the Emperor Go-Daigo as duty smith (後醍醐天皇の御番鍛冶); Honma notes the rare blades with a sixteen-petal chrysanthemum crest (十六葉の菊花紋) below the that lend the tradition weight. In the school's work "Yamashiro-style elements are intermingled within the tradition" (備前伝の中に山城風が混在), with no small influence from the school of neighboring besides, so that the line is called "a distinctive presence among works" (備前物中異色の存在). Fujishiro grades Unsho Jo .
The trait the judges name first is the curvature: a slender with at the base and a small point, arching evenly in a high wa-zori, the curve. The published sources observe that "whereas the work of the period is , it presents wa-zori" (同時代の長船物が腰反りであるのに対して輪反りを呈している). He excelled in , narrow to medium, mixed with , and shallow . The slant in reverse in the manner, and here and there wedge-shaped shadowy enter. The tightens, carries and at times sinks subdued; and fine run along the edge. Now and then the temper falls away slightly at the , and the published sources note that "the at the base may be called Unsho's individuality" (元の焼落しは雲生の個性). The turns back round, or tending larger; even of a blade steeped in character the published record observes that his particularity shows exactly where "the does not point" (帽子が尖らず). The two-character sits toward the above the , the character Sho set right of , his habit of hand; Honma takes the comparatively large of this type for the first generation.
The is , in places knit to or mixed with , with and fine , and a stands. Characteristically it is what the published sources describe as "the black peculiar to the Unrui, as if pressed in with the pad of a finger" (指の腹で押したような雲類独特の黒い地斑映り), and the steel color besides tends somewhat blackish. Honma counts it a point of interest that these late blades carry in both and , at times with "an even more vivid than in work" (まま極めて長船物以上に鮮明な映り).
The published sources state his range in one sentence: "his representative manners are two" (代表的作風は二様あって). In one, standing with , in the with a reverse tendency, and ; in the other, closely knit , the especially distinct, the tight. The of session 7 belongs to the former, with an old-toned as if pressed in with a finger (指で押した様な古調な映り). Beyond the pair lies a stronger vein. "Unsho's manner is mostly low in temper and somewhat lonely in its activity" (雲生の作風は焼きの低いやや働きの寂しいものが多く), yet other works are known with a somewhat wider , conspicuous and and strongly attached , a make that connects to Unji; the folded-signature of session 21 is read exactly so, his work at full power. At least two generations are recognized, the second placed around Bunpo or Kenmu; the registers transmit the first Unji as his son, or by another account his younger brother. Long signatures are exceptional: the signed no Unsho (備前国雲生) is called a signature almost without parallel (他に類例が殆ど無く).
His position within is the published sources' own formula: the work of the line, beginning with its curvature, is reckoned "the closest to Kyoto work" (最も京物に近い) among products, and individual blades can be confounded with the school or with neighboring . His holds the Kyoto level while his run in the way. Yet the clearly defined keeps the flavor of his native tradition strongly present, and where the make breathes , the round remains his own. The judges divide the by the temper: his mostly low and quiet in its activity, that of Unji wider and strongly -laden, with and standing out. The more powerful of his own blades are read as approaching his successor; the line continues through Unshige.
Seventy-four designated works stand on record. Six are Important Cultural Properties, held as cultural patrimony, and nine more were designated Bijutsuhin before the war, among them a counted one of the thirty-five blades hand-picked by Uesugi Kagekatsu (上杉景勝御手選び三十五腰), the of Iwasaki Koyata, now in the Seikado Bunko Art Museum, and the passed from Tokugawa Iesato to the Sano Art Museum. Fifty-seven blades stand in the and tiers. Signed works are comparatively numerous for so early a smith, thirty-eight signed against thirty-four unsigned here, nearly all the two-character . Ten blades carry recorded provenance: the of session 12 descends in the Uda Mori, a cadet line of the Nagato Mori; an Asano house carries a Kocho of 1676 valuing it at ten gold pieces; others passed through the Okochi house and the Imperial Family. The Important Cultural Properties and the museum holdings will not move. What a collector may realistically encounter is a blade, an attributed on the wa-zori, the dark and the -laced , or one of the signed ; a signed comes to open hands only rarely, and is an event in the field when it does.