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.

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#).

Futokorogatana Kaiken Tanto

Futokorogatana (懐刀) is translated as “clothing fold sword” and describes a type of tanto mounting meant to be carried in the kimono sleeve or fold. Also known as kaiken, this humble style of hidden mounting is usually unadorned with a smooth profile and lacquer finish. More photos and information.

Process: Making the Fittings – Aikuchi Tanto Koshirae

The fuchi and koiguchi are from a reclaimed buffalo horn souvenir, the kurikata is from a reclaimed horn button, the wrapping is rawhide samegawa, the mekugi is copper and silver. All of the parts are first shaped and fit, then the samegawa is wet formed to the handle contours, dried, and then attached with sokui (rice paste glue). After the scabbard and handle are lacquered, the horn parts will be polished and attached with sokui as well. The mekugi cap is soldered on with hard silver solder in the charcoal forge. carving the inside | carving the outside | final work

Process: Carving the Tsuka & Saya – Aikuchi Tanto Koshirae

In this video the tsuka is carved first, starting with the fuchi end and then the kashira area, carving the profile outlines and then removing the material in between before carving the final shape and sculpting the details. The saya is next, first dimensioning the blank is to approximate size and then profiling the koiguchi and then the kojiri, removing the material and carving as close as possible to the final shape using kanna and kiridashi. Finally any remaining high points in the curves are smoothed with a fine rasp. carving the inside | making the fittings | final work

Process: Carving the Inside – Aikuchi Tanto Koshirae

In this video the tsuka is carved first, starting with the omote side and then the ura, carving each half from the mune to the ha. The saya is next, starting with the omote and then the ura, each half beginning with the fitting of the blade (from the mune towards the ha) and then the fitting of the habaki area (koiguchi). Finally the halves are glued together with rice paste glue, wrapped with leather cord, and wedged tightly to dry overnight. The first half is almost real time, the repeat steps edited out during the second half. The wood is hounoki, carve carefully and check often! carving the outside | making the fittings | final work