Sunnobi Tanto Blade w/Habaki

$1400

A 310mm hammer-forged tanto blade with Showa period iaido habaki.

Out of stock

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Description

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 satoyama style blade is ready to be mounted as an outdoor knife in takedown style.

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 antique steel.

Island Blacksmith: Charcoal forged knives from antique steel.

Forged from a reclaimed cultivator tine, the tapering blade proportions of this tanto are a slightly scaled up interpretation of a famous national treasure tanto known as the kenshinkagematsu. It has a small amount of graceful koshizori, and the edge temper of this high carbon steel blade has been left relatively hard as it would be in a classical sword.

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, sharpening, or even handle replacement.

The iaido habaki (not pictured) is non-traditionally made (cast) but functional (ductile) brass and could use some filing on the cheeks/sides in a couple of places but fits as-is.

The blade is just under 12.25″ long with an overall length of 16 3/8″. The spine at the munemachi is about 6mm thick. The edge has been taken down to around 1/2mm but still needs a final sharpening. The unhardened tang is not yet drilled, the general location can be marked if requested.

Specifications

長さ/刃長 Nagasa (blade length): 310mm (10.2sun)
重ね/元重 Motokasane (spine thickness): 6mm
元幅 Motohaba (blade width): 30mm
反り Sori (curve): 2mm, slight koshizori
中心/茎 Nakago (tang length): 107mm
柄長 Tsuka (handle length): none (should be ~11-13cm)
拵全長 Koshirae (overall): none (should be ~48-52cm)

形 Katachi (geometry): hira-zukuri, iori-mune
刃文 Hamon (edge pattern): suguha (with mizukage)
帽子/鋩子 Boshi (tip pattern): ko-maru
中心/茎 Nakago (tang): futsu, kuri-jiri, no mekugi-ana
銘 Mei (signature): mumei (unsigned)
拵 Koshirae (mounting): none

Materials: vintage cultivator tine steel, Showa era brass habaki

This piece is in a private collection in Hawaii.

Island Blacksmith: Charcoal forged knives from antique steel.

Island Blacksmith: Charcoal forged knives from antique steel.

Process

This blade was forged and underwent yaki-ire at the museum forge. It began as a pre-1960s (integral) cultivator tine used by a farmer a generation or more ago.

Island Blacksmith: Charcoal forged knives from antique steel.
The starting point as a lengthwise half of a pre-1960s (integral) cultivator tine.
Island Blacksmith: Charcoal forged knives from antique steel.
After the tine has been straightened the sunobe (preform) is forged with all tapers and proportions in place.
Island Blacksmith: Charcoal forged knives from antique steel.
During the hizukuri stage the peaked spine is forged in first, followed by the bevels.
Island Blacksmith: Charcoal forged knives from antique steel.
After the final heat for the forging stage the steel is heated evenly to normalize, removing any stresses remaining from forging.
Island Blacksmith: Charcoal forged knives from antique steel.
After filing the notches and the spine some additional adjustment is necessary along the bevels.
Island Blacksmith: Charcoal forged knives from antique steel.
The bevels are filed slightly along the edge to clean them up before hardening.
Island Blacksmith: Charcoal forged knives from antique steel.
After a final round of normalizing again, heating to an even temperature and then cooling slowly in air.
Island Blacksmith: Charcoal forged knives from antique steel.
Preparing the mixture of charcoal, clay, stone powder, and water.
Island Blacksmith: Charcoal forged knives from antique steel.
The clay mixture will control the cooling rate of the main part of the blade during yaki-ire.
Island Blacksmith: Charcoal forged knives from antique steel.
After yaki-ire–the exposed edge has cooled quickly and become very hard, the blade has gained some curvature.
Island Blacksmith: Charcoal forged knives from antique steel.
The area protected by the clay layer cools about half a second slower as it hits the water and remains in a tough, ductile state.
Island Blacksmith: Charcoal forged knives from antique steel.
The clay is cleaned off, the hardness checked, and the blade is tempered slightly over the flames.

Island Blacksmith: Charcoal forged knives from antique steel.

Island Blacksmith: Charcoal forged knives from antique steel.

**Please note that in order to preserve the patina and texture of the antique components involved in this mounting there may be minor damage, scuffs, variations in colour, and other indications of their stories over the centuries.

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