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

Sadakane, a swordsmith of the Ichimonji school in Fukuoka, Bizen no Kuni in the era of Hoji (1247 to 1249), is said to be the son of Munetada. His sword style, however, is more old-fashioned than that of his father Munetada. The slim blade with the relatively high ridge line, koshizori (swords with the deepest part of the curve close to the tang) and kokissaki (a small blade tip) is typical of tachi (swords made to be worn with the cutting edge down) of the early Kamakura period. The jigane (ground metal) has a wood grain pattern with a light utsuri (a white misty formation that runs parallel to the hamon in the ground metal) whereas the hamon (blade pattern) features a mixture of komidareba (a small irregular pattern) and kochojiba (a small clove pattern), lots of konie (small martensite crystals) and a deep nioiguchi (the dividing line between the hamon and the ground). These characteristics also resemble those of Ichimonji school swords in the early Kamakura period. It was handed down to the Arima family in the Kurume domain, Chikugo no Kuni during the Edo period and accompanies the koshirae (outer fittings) for an itomakitachi (a sword where the area around the handle and the area that touches the hip are wrapped with strings).