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

Although there are various views as to the provenance of this sword, it is generally believed that the emperor at that time gave it to Minamoto Yorimasa to honor his killing of a monster. It was later given to the Toki family and in 1882, Toki Yorichika presented it to Emperor Meiji via Higashikuze Michitomi.
　Deeply curved near the hilt, the slim blade has an antique and refined shape of the late Heian period with a fushigokoro (slightly bent downward) tip. The jigane (the ground metal) has a wood grain pattern in hadadachigokoro and shirokeutsuri (a vague 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) is in the suguha (straight) style with a narrow nioiguchi (the dividing line between the hamon and the ground metal). Due to the high shinogi (the ridgeline) and the strong shinogiji (an area between the shinogi and the back of the blade) with a masame-hada (a straight grain pattern), it is believed that this sword was made in Yamato no Kuni in the late Heian period.
　For the koshirae (outer fittings), the hilt, sheath and metal fittings are all black lacquered and blue thread is wrapped around the sheath. It seems that originally, the hilt was also wrapped with thread. This type of sword with black lacquered koshirae is depicted in many picture scrolls as a sword in common use among samurai. The year of creation seems to be in the late Kamakura period.