National Treasures & Important Cultural Properties
of National Institutes for Cultural Heritage, Japan

Among the swordsmiths in Bizen no Kuni, those in the early Kamakura period before the emergence of the Ichimonji school are called Kobizen. Yoshikane is one of them. This is a slim sword with a deep koshizori (the deepest part of the curve near to the tang), which has an antique and refined sugata (the shape of the blade) with a kokissaki (small tip of the blade). While the jigane (ground metal) shows a mixture of itamehada (a wood grain pattern) and mokume-hada (a round grain pattern similar to itame) with utsuri (a white misty formation that runs parallel to the hamon in the ground metal), the hamon (literally "blade pattern," which is a visual effect created on the blade by the hardening process) shows komidare (a small-scale irregular blade pattern) and kochoji (a small clove pattern) with little difference in height. There is konie (small martensite crystals) in the blade and kinsuji (small shiny lines) in the monouchi (one-third of the blade toward the tang), giving a more aggressive impression compared to the blades of other Kobizen swords. This sword was given to prince Katsuranomiya (a member of the Imperial Family) by Tokugawa Iemitsu in 1626 when the prince visited Nijo Castle.