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

Kanetsugu was one of several sword makers who were also known by the moniker Furu-aoe and were active in the early Kamakura period (1185-1333) in Aoe in Bicchu province (present-day western Okayama prefecture). The sword's narrow blade with a small end and a large curve at the bottom was commonly produced by sword makers of the time in other areas as well. This sword is typical of what is known as Furu-aoe for its temper line along the blade's edge consisting of a straight line (J., suguha), fine jagged lines (J., komidare) and small wavy lines (J., gunome); also noteworthy is the wood-grain texture of the metal surface with its small cross-grain pattern called "fine wrinkles" (J., chirimen-hada) and the maker's name inscribed on the side worn next to the body.