The blade accompanied by a certificate of registration as a Juyo Token [Important Sword] no. 8757 issued by the Nihon Bijutsu Token Hozon Kyokai [Society for the Preservation of the Japan Art Sword] on 25th May 1990
The three successive generations of the smiths Unsho, Unji, and Unju lived at Ukan no So in Bizen province (present-day Okayama prefecture) the main centre for the production of swords during the 13th and 14th centuries. The name of their village 'Ukan' was later written as 'Ugai', and the school has been known by both names. They became known as the 'Unrui', or 'Kumo' school from the first character un (read Kumo - cloud) of their names. It is said the first generation Unsho together with his son Unji made a sword or swords for the Emperor Godaigo, who gave them the Kumo character.
The blades differ from those of other schools in Bizen province at the time, and they display characteristics of the Aoei group of neighbouring Bitchu province. Unsho is thought to have originally moved from Yamashiro to Bizen, and both Yamashiro and Yamato influences can be detected in his work, Unji is believed to have been most active during the second decade of the 14th century, and his son thereafter, although some authorities suggest four generations of the school. It is difficult to distinguish between the signatures of the first and second generations, but the even curve and lack of fumbari on this sword would suggest work of the second generation who was active around the middle of the 14th century. It is altogether a beautiful and healthy example of the work of the school.