Sunnobi tanto (寸延び短刀) are larger than ordinary tanto, with nagasa a sun or two above 1 shaku (sun nobi, “a sun longer”, from nobiru, to stretch or lengthen). Though there is some area of crossover with hira-zukuri ko-wakizashi and they may have sori similar to ko-wakizashi, the simplified difference would be that they are still designed with tanto geometry rather than wakizashi proportions and form. This is the first hammer-finished sunnobi tanto and also the first mounted in kura style, using reclaimed sword parts.
The core of this project is a charcoal-forged blade, water quenched with clay and sharpened with waterstones, an outdoor knife that has the foundation of the Japanese sword. The aikuchi style mounting is in the rustic kura (蔵, storehouse) style and includes antique fittings from swords carried generations ago and bearing the patina of the ages.
Satoyama are the managed forest areas that border the cultivated fields and the mountain wilds in Japan. Historically they provided soil nutrients, firewood, edible plants, mushrooms, fish, and game, and supported many local industries and crafts such as farming, timber construction, and charcoal making. The interaction of forest, arable land, wetlands, and streams are an important component of the satoyama landscape.
The subtle appearance of hammer marks and file teeth on the blade, the rustic carved and lacquered wooden mountings, paired with reclaimed sword fittings—treasures from the kura storehouse. A hand crafted tool for adventure that would be very much at home in the field, forest, or mountain landscape.
Forged from an antique chisel that was forged from an older file decades ago, the blade profile of the mountain style tanto is based on a classical sunnobi tanto and has a wide blade with subtle sori (curvature) that is accentuated by the mounting. The temper of this high carbon steel blade has been left relatively hard, a particular combination of steel and heat treatment that is well suited to users who require a good edge and are willing to take care of it.
The tang is constructed in a similar manner to a Japanese sword requiring only a single bamboo peg to hold the knife assembly together. In addition to the sense of beautiful simplicity, this design allows the knife to be taken apart for cleaning and sharpening work.
This tanto was specifically forged to fit a large antique Edo period copper katana habaki. Reclaimed brass sword fittings form the ferrule and koiguchi (scabbard mouth) and the seppa (blade washer) came from a Showa era gunto mounting. The handle is carved from Magnolia and reinforced with polished and lacquered rayskin in a spiral wrap. The kurikata (cord loop) is carved from buffalo horn and lacquered, and the mekugi (removable peg) carved from susudake smoked bamboo, darkened from serving many decades as part of a ceiling above the hearth in a kominka farmhouse. The scabbard is carved from Magnolia and lacquered in a dark chocolate wine colour made from natural urushi, black urushi, and ground red crimson lake stone pigment.
The blade is 11.5″ long with an overall length of 17.25″ and just under 18.5″ when sheathed. The spine at the munemachi is 7mm thick.
長さ/刃長 Nagasa (blade length): 292mm
重ね/元重 Motokasane (spine thickness): 7mm
元幅 Motohaba (blade width): 34mm
反り Sori (spine curve): 3mm
中心/茎 Nakago (tang length): 100mm
柄長 Tsuka (handle length): 123mm
拵全長 Koshirae (overall): 473mm
形 Katachi (geometry): hira-zukuri, iori-mune, with ubuha
刃文 Hamon (edge pattern): rising suguha
帽子/鋩子 Boshi (tip pattern): ko-maru
中心/茎 Nakago (tang): futsu, kuri-jiri, one mekugi-ana
銘 Mei (signature): mumei (unsigned)
拵 Koshirae (mounting): satoyama kura style aikuchi, issaku (sole authorship) plus 4 reclaimed/antique parts
Materials: antique file steel, Magnolia, buffalo horn, samegawa, reclaimed/antique fittings, natural urushi lacquer, crimson lake
This piece is available online.
This blade was forged and yaki-ire performed at the museum forge. It began as an old chisel that was hand forged from an even older file decades or perhaps generations ago. The remaining piece of the steel billet became the Koi-oshidori Field Kotanto.