Nihonto Glossary Nihonto History
Koshi-zori : a type of blade curve which has its center nearer the tang (nakago) than the point (kissaki). It is typical of early blades from late Heian to mid-Kamakura, espeically blades from Bizen province.
Wa-zori : a type of blade cuve which center is on the middle.
Saki-zori : a type of blade curve which center is near to the kissaki.
Yasurime : a general term for filemarks on the nakago. These were often added by the smith to serve as a kind of additional signature.
Boshi : the part of the tempered edge (hamon) which is in the point of the blade (kissaki). It is particularly important to make a thorough examination of the boshi when assessing a sword.
Yokote : the transverse ridge separating the kissaki from the rest of the blade. It runs from the edge (ha) as far as the ridge (shinogi).
Ha : a general term for the tempered edge of the blade. More precisely, called the yakiba.
Shinogi : the ridge on the side of a blade and running along its length, usually near the back (mune) than the edge (ha).
Ji : a general term for the surface structure of the blade between the ha and the shinogi.
Hamon : a general term for the shape of the outline of the border between the ha and the ji.
Nie & Nioi : hard bright areas of steel of martensitic crystalline structure, resulting from the tempering process and forming the hamon, by standing out in contrast to areas of softer pearlite structure. Nie are individually descernible to the naked eye, in contrast to nioi, which are technically the same but which do not show up as discrete globules of steel without magnification and consequently appear as a mist or cloudlike feature of the polished metal.
Chikei : brightly shining areas of curved outline occuring in the ji.
Sunagashi : lines of nie in the ha, parallel to the hamon.
Muranie : Uneven nie, irregular particles, much larger than most nie which partially intrude upon the hamon.
Kinsuji : brightly shining curved thread-like areas in the ha. They resemble chikei, which occur in the ji.
Yo : areas of martensitic structure in the hamon, like ashi but detached and leaf-shaped.
Ashi : lines of martensitic structure projecting into the ha at right angles to the hamon. Saka-ashi means oblique ashi.
Utsuri : a cloudy area of bright crystalline metal bordering the hamon and ofter appearing to be a reflection of it in the ji. It is separated from the hamon by a darker area of non-reflective quality.
Uchinoke : similar to short nijuba, but resembles crescent moons and appear in the ji near the habuchi.
Nijuba : a second line of hamon, consisting of nie or nioi and appearing parallel to hamon.
Habuchi : the border between the ji and the hamon, also known as nioi-guchi.
Hotsure : a streaky, brushed-looking area which sometimes occurs on the hamon.
(Ji)hada : the surface-grain pattern or the pattern of the surface texture of the steel produced in the forging process.
Itame : the commonest hada and resembles the surface of a wooden board cut against the grain.
Masame : a hada shows a straight grain with lines running parallel to the length of the blade.
Mokume : a hada looks like a burl wood-grain.