Tombo Mountain Kotanto

The core of this project is a high carbon blade, charcoal-forged from reclaimed steel, water quenched with clay and sharpened with waterstones, an outdoor knife that has the foundation of the Japanese sword but is finished in the simple and humble style of farming and foresting tools of centuries ago.

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.

Island Blacksmith: Charcoal forged knives from reclaimed steel.

Island Blacksmith: Charcoal forged knives from reclaimed steel.

The subtle and rustic appearance of hammer marks on the blade and hand-carved wooden handles finished with natural urushi lacquer made from tree sap—reminiscent of hand-hewn beams in a kominka farm house that are darkened by years of smoke drifting up from the irori hearth. A hand crafted tool for adventure that would be very much at home in the field, forest, or mountain landscape.

Forged from century-old mining car rail, the wider blade profile of the mountain style kotanto is based on proportions of a classical katana and this blade has a tapering takenoko (bamboo shoot) shape with a drop point. This blade retains some of the original pitting along with the forged hammer texture. The temper of this high carbon steel blade has been left relatively hard in order to hold a keen edge. This particular combination of old steel and heat treatment 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, polishing, detailed cutting tasks, or major resharpening work.

Island Blacksmith: Charcoal forged knives from reclaimed steel.

Island Blacksmith: Charcoal forged knives from reclaimed steel.

The handle and scabbard are carved from local magnolia and finished with traditional unfiltered urushi lacquer with undertones of black to highlight the facets of the wood in certain light. An organic bean-shaped forged copper hamidashi style guard and vintage tombo (dragonfly, symbolizing pressing on to victory without retreat) sword fitting complete the handle and a hammer textured copper koiguchi and horn kurikata accent the scabbard. The removable peg is carved from susudake, a piece of bamboo that served for a century or more as part of the ceiling or inside thatched roof structure in a kominka, darkened and hardened by decades of smoke wafting up from the irori hearth.

The blade is 5.5″ long, the overall length is about 10″, and 11.5″ when sheathed. The spine at the munemachi is about 6mm thick.

Specifications

Nagasa (blade length): 137mm
Motokasane (blade thickness): 6mm
Motohaba (blade width): 31mm
Sori (curve): strong takenoko with drop point
Nakago (tang): 93mm
Tsuka (handle): 112mm
Koshirae (overall): 292mm

Katachi (geometry): hira-zukuri, iori-mune, with ubuha
Hamon (edge pattern): suguha
Boshi (tip pattern): ko-maru
Nakago (tang): futsu, kuri-jiri (as forged), one mekugi-ana
Mei (signature): mumei (unsigned)
Koshirae (mounting): satoyama hamidashi style, issaku (except for the reclaimed fuchi, koiguchi)

Materials: reclaimed mine car rail steel, scrap copper, vintage copper sword fitting, Magnolia, water buffalo horn, natural urushi lacquer, susudake Bamboo

This piece is available online.

Island Blacksmith: Charcoal forged knives from reclaimed steel.

Island Blacksmith: Charcoal forged knives from reclaimed steel.


Process

This knife began as a century-old mining car rail that was heavily pitted by rust. This was the first blade of the season that was forged and underwent yaki-ire at the museum forge documented by photographer Jourdan Causey. The handle and scabbard were crafted at the museum during the summer demonstrations.

Island Blacksmith: Charcoal forged knives from reclaimed steel.
This blade was forged from the web of a century-old mining car rail that was deeply pitted by rust.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Working on the blade at the museum. Photo by Jourdan Causey.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
After the initial hammer work, preserving the entire original volume of steel as much as possible before filing to clean up the profile.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Temperature of the metal is determined by colour. Photo by Jourdan Causey.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Some of the forging of this blade was documented during a visit from a talented LA-based photographer.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Adding the thin clay layer to delay the cooling of the body of the blade during yaki-ire (hardening).
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The blade cleaned of clay after surviving the stressful process of yaki-ire, other than the edge the original century of pitting and hammered surface has been preserved on the blade. The strip along the edge is now very hard while the rest of the blade remains tough and ductile, the best of both realms.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The organic bean-shaped guard is forged from a piece of electrical copper, the edge carefully peened to upset (widen) the rim and then the opening is filed to fit the tang.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
A slab of Magnolia is sawn into a blank to form the tsuka (handle) and saya (scabbard) and flattened inside with a kanna (handplane).
Island Blacksmith: Charcoal forged knives from reclaimed steel.
After choosing the best grain direction, the tsuka (handle) blocks are carved inside to fit the tang precisely.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The tsuka is glued back together with sokui (rice paste glue), wrapped with leather, and wedged for tension overnight to dry.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The tsuka is carefuly carved and planed down toward its final shape and size, leaving some facets for the final surface.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
After carving a shoulder for the fuchi (ferrule), the final length is determined and the pommel carved.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
A look at the assembled handle at this stage while the location for the mekugi (bamboo peg) is chosen.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The corresponding location for mekugi-ana (peg hole) is drilled in the tang with a hand powered post drill.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The mekugi (retaining peg) is carved from susudake, bamboo that has spent the greater part of a century as part of the ceiling or roof inside a kominka farmhouse, darkened and strengthened by the smoke from the hearth.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
It is carved in such a way as to leave the strong grain of the bamboo’s outside wall running full length along the back edge of the peg (facing toward the pommel).
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The inside of the saya (scabbard) halves are carefully carved to fit the blade and hold it snugly as best as possible despite the lack of a habaki.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Glued with sokui, realigned carefully, and wrapped to dry overnight.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Wedges increase the clamping force and provide extra tension and pressure where needed while drying.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
The rough sawn saya block after removing the cord and wedges, note how the grain curves slightly along the direction the finished shape will flow.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Excess wood is removed from the scabbard with kanna (wood block plane), from four sides to eight sides to sixteen and so on taking thinner shavings until it aligns with the handle and the final shape is achieved.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
A small shoulder is carved for the forged copper reinforcement at the koiguchi (scabbard mouth).
Island Blacksmith: Charcoal forged knives from reclaimed steel.
A kiri (hand drill) and small round file are used to make the mekugi-ana (peg hole) in the handle to align with the one in the tang and the parts are mainly completed.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Handle and scabbard ready for lacquering with natural tree-source urushi.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
After lacquering with several layers of unfiltered natural urushi lacquer made from the sap of a certain tree the horn kurikata (cord loop) is installed in a sliding dovetail groove.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Ready for final assembly. The koiguchi and kurikata will be fixed in place with nikawa (hide glue).
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Subtle darker layers under the natural urushi give depth and highlight the hand carved tool marks.
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Omote (front/public side)
Island Blacksmith: Charcoal forged knives from reclaimed steel.
Ura (back/private side)

Island Blacksmith: Charcoal forged knives from reclaimed steel.

Island Blacksmith: Charcoal forged knives from reclaimed steel.