Arashiage: Filing Order of Operations

Arashiage is the stage of rough shaping following hizukuri (forging) and in preparation for yaki-ire (hardening). Earlier posts have described tanto kata and the geometry of the tang, machi, blade, and kissaki. Familiarity with these geometry points is a prerequisite to success in this stage. This post will… Continue reading

Differential Hardening Sunnobi Tanto

Sunnobi tanto are larger than ordinary tanto (nagasa above 1 shaku) and may have sori similar to ko-wakizashi. Read more about the process of yaki-ire.

1. Using approximately a 1:1:1 mixture of natural clay, polishing stone powder and ground charcoal to mask the back of a hand forged blade about 1-1.5mm thick to slow down the cooling rate.
2. Brushing on a thin slip layer with extra charcoal added along the exposed edge to speed up the cooling rate and protect from carbon loss.
3. Carefully heating in a charcoal forge supplied by air from a fuigo box bellows until the edge reaches critical temperature.
4. Plunging edge-first into cold rainwater to cool the blade quickly and harden the edge while leaving the rest tough and resilient.
5. Testing for successful hardening with a file and then removing the clay with a mild steel scraper.
6. Slightly reheating the blade over the flames to temper the edge.
7. Test polishing on a coarse Japanese waterstone to check the hamon.

Process – Making habaki with simple tools

Making a habaki from reclaimed copper. Material is scrap copper from an electrical bus bar, forged and bent to shape, silver brazed with hard silver solder in the charcoal forge with fuigo, finish work done with files and rasps. Watch the shorter overview edit here.

Yakiire – Traditional Clay & Water Quench

The immersive experience of being in the darkened workshop during a traditional clay and water quench using a charcoal forge. A hamon is created on a tanto using a 1mm thick layer of roughly 1:1:1 natural clay, charcoal powder, and polishing stone powder. The blade is about 29cm long (nagasa), 2.3cm wide (motohaba) and 6mm thick (motokasane). The final shot shows the rough kajitogi polish to check the hamon placement using a very coarse waterstone (torajirushi 80#, lobstercarbon 120#).

Making a Kanna from a Reclaimed Chisel

A custom mameganna (small “bean” plane) such as might be used by furniture makers can be made fairly quickly from an old chisel. This type of kanna might be used for shaping saya or tsuka or for other small woodwork projects requiring a custom radius or access to… Continue reading

温故知新・On Ko Chi Shin

A true and accurate understanding of the past is an important step towards a good future. 温故知新 (on ko chi shin) is an expression that most directly translates to, “study the old to know the new”. This one-of-a-kind project represents the current progression of my work based on… Continue reading

Komori~san back in the forge

Komori~san and his talented crew came to the island and spent a couple of days getting footage in the forge and of the final assembly of a tanto. They set up all their own lighting in the forge, and along with a couple of cameras, location sound, and… Continue reading

Aikuchi Tanto Koshirae

A custom koshirae for a small antique tanto blade belonging to a client. Crimson lacquered samegawa handle, fukiurushi horn fittings, a silver mekugi, and polished black lacquer scabbard in a classical aikuchi style. Materials for the custom red and black aikuchi style koshirae mounting include lacquered samegawa over… Continue reading