This antique Japanese Katana is attributed to the Ukai school, active in Bizen province from the late Kamakura to Nanbokuchō period. It comes with an NBTHK Tokubetsu Hozon Certificate, shirasaya, and Tachi Koshirae. The blade features a dragon-motif Menuki and is stored in a Tachi-style mounting.
mumei · Ukai · Koto · nagasa 66.3cm · sori 2.3cm


























Bizen-den · Bizen
7 pieces on the market now
At Ukan-no-shō in Bizen Province, a place name later written Ukai, a small group of smiths worked from the close of the Kamakura period into the first decades of Nanbokuchō, every one of them setting the character Un, 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-Nanbokuchō, his dated Jōji tachi 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 habaki lend that account its weight. The make that resulted stands apart from the Osafune mainstream: within an essentially Bizen body the members describe a Yamashiro cast intermingled, with no small influence from the Aoe school of neighboring Bitchū besides, so that the published sources call the line a distinctive presence among Bizen works. The shared vocabulary begins with the curvature: a slender tachi with funbari at the base and a small point, arching evenly in a high wa-zori where the Osafune work of the same generation runs koshizori, the papers reading that even arch as close to Kyoto work. Against the chōji of the mainline the Ukai hands temper suguha, narrow to medium, mixed with ko-gunome, ko-chōji, shallow notare and a small midare, the ashi and yō entering thickly and slanting in reverse in the Aoe manner; kinsuji, sunagashi and hotsure work along the edge, and the nioiguchi now tightens under ko-nie, now sinks subdued. The jigane is itame mixed with mokume, knit to ko-itame on the finer blades, with ji-nie, fine chikei and a steel color tending blackish, across which stands a midare-utsuri; the group's own signature is what the papers call the black jifu-utsuri peculiar to the Unrui, as if pressed in with the pad of a finger.
The bōshi turns back round, ko-maru, and the round turn that does not point is held the school's particularity even where the make breathes Aoe. Within that common ground the members divide by temper: Unshō's yakiba is mostly low and quiet in its activity; Unji is the nie hand, his line wider and strongly nie-laden with ashi and yō standing out, his hada flowing and at times masa-tinged; Unju presses the idiom toward the Nanbokuchō with deepening nie and a scantier utsuri, his most Yamato-leaning blades running almost into masame with kuichigai-ba and a yakizume sweep. To kantei Ukai work is to read the line as the closest to Kyoto work among Bizen products: the wa-zori and even arch, the dark jifu-utsuri, the suguha laced with saka-ashi, and the round bōshi that settles a blade which might at first sight be confounded with the Rai school or with neighboring Aoe. The judges separate the hands by the activity of the ha, hotsure and stronger nie carrying an unsigned blade to Unji rather than Unshō, the reverse-chisel strokes of the mei and the date cut straight beneath a long signature answering to Aoe 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 ō-suriage mumei katana attributed on the silhouette and the cloud-group traits, or, far less often, a signed tachi; 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. Learn more →
| Smith | Era | Designated |
|---|---|---|
| Unsho雲生 | 1303-1306 | 72 |
| Unji雲次 | 1315-1335 | 131 |
| Unju雲重 | 1352-1375 | 60 |
| Unsho雲生 | 1317-1319 | 0 |
| Unju雲重 | 1384-1394 | 0 |
A Hozon-certified blade judged to show notably superior workmanship and a better state of preservation. The bar is higher: re-tempered blades and most unsigned Muromachi/Edo works are excluded.
The NBTHK (Nihon Bijutsu Tōken Hozon Kyōkai, the Society for the Preservation of Japanese Art Swords) is a public-interest incorporated foundation founded in 1948 and supervised by Japan’s Agency for Cultural Affairs (Bunkachō); it is based at the Japanese Sword Museum in Tokyo. Its expert panels physically examine each submitted work (shinsa) and issue a certificate (kanteishō) ranking it by artistic and historical merit. NBTHK papers are the most widely recognized standard of authentication for Japanese swords and fittings.
NBTHK official siteReturns/exchanges limited to defects caused by shipping (except willful misconduct or gross negligence by the company); customers must contact within 72 hours of receiving the product.

This antique Japanese Katana is attributed to the Ukai school, active in Bizen province from the late Kamakura to Nanbokuchō period. It comes with an NBTHK Tokubetsu Hozon Certificate, shirasaya, and Tachi Koshirae. The blade features a dragon-motif Menuki and is stored in a Tachi-style mounting.
mumei · Ukai · Koto · nagasa 66.3cm · sori 2.3cm


























Bizen-den · Bizen
7 pieces on the market now
At Ukan-no-shō in Bizen Province, a place name later written Ukai, a small group of smiths worked from the close of the Kamakura period into the first decades of Nanbokuchō, every one of them setting the character Un, 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-Nanbokuchō, his dated Jōji tachi 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 habaki lend that account its weight. The make that resulted stands apart from the Osafune mainstream: within an essentially Bizen body the members describe a Yamashiro cast intermingled, with no small influence from the Aoe school of neighboring Bitchū besides, so that the published sources call the line a distinctive presence among Bizen works. The shared vocabulary begins with the curvature: a slender tachi with funbari at the base and a small point, arching evenly in a high wa-zori where the Osafune work of the same generation runs koshizori, the papers reading that even arch as close to Kyoto work. Against the chōji of the mainline the Ukai hands temper suguha, narrow to medium, mixed with ko-gunome, ko-chōji, shallow notare and a small midare, the ashi and yō entering thickly and slanting in reverse in the Aoe manner; kinsuji, sunagashi and hotsure work along the edge, and the nioiguchi now tightens under ko-nie, now sinks subdued. The jigane is itame mixed with mokume, knit to ko-itame on the finer blades, with ji-nie, fine chikei and a steel color tending blackish, across which stands a midare-utsuri; the group's own signature is what the papers call the black jifu-utsuri peculiar to the Unrui, as if pressed in with the pad of a finger.
The bōshi turns back round, ko-maru, and the round turn that does not point is held the school's particularity even where the make breathes Aoe. Within that common ground the members divide by temper: Unshō's yakiba is mostly low and quiet in its activity; Unji is the nie hand, his line wider and strongly nie-laden with ashi and yō standing out, his hada flowing and at times masa-tinged; Unju presses the idiom toward the Nanbokuchō with deepening nie and a scantier utsuri, his most Yamato-leaning blades running almost into masame with kuichigai-ba and a yakizume sweep. To kantei Ukai work is to read the line as the closest to Kyoto work among Bizen products: the wa-zori and even arch, the dark jifu-utsuri, the suguha laced with saka-ashi, and the round bōshi that settles a blade which might at first sight be confounded with the Rai school or with neighboring Aoe. The judges separate the hands by the activity of the ha, hotsure and stronger nie carrying an unsigned blade to Unji rather than Unshō, the reverse-chisel strokes of the mei and the date cut straight beneath a long signature answering to Aoe 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 ō-suriage mumei katana attributed on the silhouette and the cloud-group traits, or, far less often, a signed tachi; 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. Learn more →
| Smith | Era | Designated |
|---|---|---|
| Unsho雲生 | 1303-1306 | 72 |
| Unji雲次 | 1315-1335 | 131 |
| Unju雲重 | 1352-1375 | 60 |
| Unsho雲生 | 1317-1319 | 0 |
| Unju雲重 | 1384-1394 | 0 |
A Hozon-certified blade judged to show notably superior workmanship and a better state of preservation. The bar is higher: re-tempered blades and most unsigned Muromachi/Edo works are excluded.
The NBTHK (Nihon Bijutsu Tōken Hozon Kyōkai, the Society for the Preservation of Japanese Art Swords) is a public-interest incorporated foundation founded in 1948 and supervised by Japan’s Agency for Cultural Affairs (Bunkachō); it is based at the Japanese Sword Museum in Tokyo. Its expert panels physically examine each submitted work (shinsa) and issue a certificate (kanteishō) ranking it by artistic and historical merit. NBTHK papers are the most widely recognized standard of authentication for Japanese swords and fittings.
NBTHK official siteReturns/exchanges limited to defects caused by shipping (except willful misconduct or gross negligence by the company); customers must contact within 72 hours of receiving the product.
