Koi-oshidori Field Kotanto

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 mounting is in the rustic kura (蔵, storehouse) style and includes antique fittings from swords carried long ago.

Island Blacksmith: Charcoal forged knives from reclaimed steel.

Island Blacksmith: Charcoal forged knives from reclaimed steel.

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 on the blade, the rustic carved and lacquered wooden mountings, paired with antique 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 even older file, the blade profile of the field style kotanto is inspired by a kamakura sword and is wider with a more pronounced belly and a slight drop point. 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.

Island Blacksmith: Charcoal forged knives from reclaimed steel.

Island Blacksmith: Charcoal forged knives from reclaimed steel.

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, polishing, detailed cutting tasks, or major resharpening work.

This knife is mounted with four antique Edo fittings that came from swords crafted or carried in that era. The centerpiece of this mounting is a delicately carved fuchi (ferrule) made from shakudo (copper, silver, and gold) inlaid with copper and overlaid with gold. Detailed katakiribori style chisel carving surrounds two characters which appear to be a wood duck (oshidori) and a koi on the banks of a stream. Japanese wood ducks are called oshidori (おしどり/オシドリ/鴛鴦) and are used in the phrase oshidori fūfu (おしどり夫婦, “a couple of lovebirds/happily married couple”). Koi-zuma (恋妻, こいづま) means loving wife and is a play on the word for koi fish (鯉).

The fuchi is paired with a katakiribori carved shakudo kashira (pommel) with bronze accents, a copper katana habaki, and bronze koiguchi all bearing the patina of the ages. The brass seppa (blade washer) is of unknown origin and may be from an iaido practitioner’s sword, but certainly has come from Japan sometime in the last several decades.

The handle is carved from local Magnolia and finished with traditional fukiurushi lacquer built up in multiple layers to darken the colour of the wood and highlight the carved facets. The scabbard is carved from Japanese Hounoki and finished with very light unfiltered traditional fukiurushi lacquer and natural tung oil. The removable peg is carved from susudake, a piece of bamboo that served for a century or more as part of the ceiling or roof in a kominka, darkened and hardened by decades of smoke wafting up from the irori hearth.

Island Blacksmith: Charcoal forged knives from reclaimed steel.

Island Blacksmith: Charcoal forged knives from reclaimed steel.

The blade is just over 3.75″ long with an overall length of 8.25″ and just over 9″ when sheathed. The spine at the munemachi is 6mm thick.

Specifications

長さ/刃長 Nagasa (blade length): 96mm
重ね/元重 Motokasane (spine thickness): 6mm
元幅 Motohaba (blade width): 29mm
反り Sori (spine curve): uchizori (drop point)
中心/茎 Nakago (tang length): 87mm
柄長 Tsuka (handle length): 102mm
拵全長 Koshirae (overall): 227mm

形 Katachi (geometry): hira-zukuri, iori-mune, with slight ubuha
刃文 Hamon (edge pattern): 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 5 antique/vintage parts

Materials: antique file steel, Magnolia/Hounoki, antique fittings, reclaimed bronze, susudake bamboo, natural urushi lacquer, natural tung oil

This piece is in a private collection in Ontario.


Process

This blade was forged and yaki-ire performed at the museum forge. It began as an antique chisel that was forged from an even older file that was used generations ago. It was originally part of the same piece of steel as the Sunnobi Mountain Tanto.

Island Blacksmith: Charcoal forged knives from reclaimed steel.
The large two-handed mukozuchi sledge is used as a one-handed bench hammer for the initial drawing out.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
After the sunobe (preform) is forged with all tapers and proportions in place the bevels are forged in.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
After forging in the bevels the machi (notches) are hand filed in.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The profile is cleaned up by a bit of hand filing, particularly to narrow it slightly along the edge.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The antique habaki fits accurately almost as-forged due to careful planning of the sunobe.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Applying the clay mixture in preparation for yaki-ire.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The clay is thoroughly dried over the coals before heating to red hot.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Heating the fire for the quenching process. At the correct temperature it is plunged into water to cool.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Upon surviving the stress of the quenching process it has become a knife, a tough blade with a hard edge.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The remaining clay is cleaned off and the blade checked for proper hardness and straightness.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
A natural sandstone is used to check hamon placement and give a softer texture to the roughly filed areas of the surface.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Shown with a sunnobi tanto kata (pattern) based on a 14th century blade by Sadamune.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The edge line at the tip and the general form of the famous tanto were the inspiration for the shape of this blade.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The scabbard is given a very thin layer of kijiro urushi and allowed to cure for several days.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
After the handle lacquer has cured the fuchi (ferrule) and kashira (pommel) are ready to install.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Ready for final assembly.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The kashira and koigichi (scabbard mouth) are attached with nikawa (hide glue) and the fuchi is pressure fit.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The kotanto in takedown disassembly state.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Fully assembled and ready, held together by a single bamboo peg.

Island Blacksmith: Charcoal forged knives from reclaimed steel.

Island Blacksmith: Charcoal forged knives from reclaimed steel.

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