During the hardening process the clay layer causes a split second difference in cooling time which creates two different hardness areas in the same piece of steel. The edge cools faster and forms a very hard steel structure called martensite while the body cools slower and forms a very tough steel structure made of ferrite and pearlite. The boundary between these two areas is called hamon and is commonly seen as a frosted line down the length of a polished sword blade.
more about the process of yaki-ire
Category Archives: Handcrafted Knives
First Lighting of the Forge & Antique Habaki Utsushi (写)
First lighting of the newly rebuilt charcoal forge in the island kajiba followed by stamping the tang and then hand forging and filing a classical tanto style habaki, silver soldered in the charcoal forge and closely based on an antique Edo period habaki. An utsushi (写) is a closely based study of another work for the purposes of professional development. Polishing and patinating will be done after the saya has been carved. information about the machigane | habaki making process
Furusato Tanto
Furusato (故郷, pronounced “foo-roo-sah-toe”) means home place or hometown and contains the ideas of being rooted or grounded wherever one may sojourn, and a confidence and longing for return. This tanto has a simple and elegant form with a natural and humble… Continue reading
SOTW #20 – Assembling the Furusato Tanto
This discarded block of wood from the Congo/Zaire sat for several years waiting for the right blade to make the best use of it. This precious dark chocolate coloured hardwood is locally called Tshikalakala or Dikela, meaning turn around or circle back, and this particular piece has a slightly curving grain that follows the line of the saya. The name Furusato (故郷) means home place or hometown and contains the ideas of being rooted or grounded wherever one may sojourn, and a confidence and longing for return. more about this project
TLDW #24 – Making an Ireko (nesting) Saya
An ireko saya (入れ子鞘, nesting scabbard) is a lining inside the saya which protects the blade from the hardwood. Furusato (故郷) means home place or hometown and contains the ideas of being rooted or grounded wherever one may sojourn, and a confidence and longing for return. This tanto has a simple and elegant form with a natural and humble mounting that reflects the rustic satoyama lifestyle and suits the aesthetics of the way of tea. more about this project
Inome Tanto
The inome (pronounced “ee-no-may”, 猪の目, eye of the boar) name comes from the pierced heart-shape designs of the decorative o-seppa (washers) on either side of the tsuba (handguard). This lovely motif is ubiquitous in Japan, seen often in architecture, furniture, and sword… Continue reading
SOTW #19 – Assembling the Inome Tanto
The inome (pronounced “ee-no-may”, 猪の目, eye of the boar) name comes from the pierced heart-shape designs of the decorative o-seppa on either side of the tsuba. This lovely motif is ubiquitous in Japan, seen often in architecture, furniture, and sword mountings. This is the first of my blades to incorporate antique sword parts as part of its mounting. Process of making the Inome Tanto.
Eyes on the Spine: say No to the kink, and Yes to the flow
One of the most common mistakes when attempting to recreate a Japanese classical style tanto is to caricature or over exaggerate certain design elements while entirely missing others. The Japanese aesthetic is subtle and nuanced, millimeter differences can make or break the… Continue reading
Yoroidoshi in Shirasaya
This blade began as a segment of reclaimed horse-drawn carriage spring and was hand forged in a charcoal fire, smoothed with files and a sen scraper, hardened using traditional water quench yaki-ire, and polished by hand with natural Japanese water stones. Crafted… Continue reading
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… 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.