Crossed Heart Forge

Historical Techniques

Hand forged with handmade charcoal, constructed and finished with historical methods and natural materials.
forging the blade

Traditional Tools

Human powered hand tools are used from the time the steel is first put in the fire through to the final assembly.
carving the scabbard

Reclaimed Materials

Steel, iron, copper, and brass are sourced from salvage and scrap wood for charcoal comes from local sources.
sourcing the materials

Behind the Scenes: How Tanto Are Made

Making Charcoal from Scrap Wood

The best forge fuel for high carbon steel tanto is softwood charcoal. The raw material is scrap wood from local sources such as furniture makers, carvers, and foresters.
The charcoal kiln is loaded, the door is put in place, the fire is tended for several hours until the steamy smoke changes colour, and then it is completely sealed until it cools down.
After completely cooling the kiln is opened and the charcoal can be chopped and sorted into grades of bladesmithing charcoal and heat treating charcoal. (Watch charcoal chopping below)

Read more about making charcoal

See the charcoal archive

Finding the Raw Materials

The blade steel is mainly curated from old homestead piles, this one formerly belonging to a blacksmith and farmer. Old farm equipment and carriage spring steel make great blades.
Potential blade steels are tested using several methods to determine their suitability and the best approach for heat treatment. The older, lower alloy steels are preferred by our inspectors.
Carbon steel takes and holds a great edge and responds well to traditional water and clay yaki-ire hardening. These carriage springs may be well over a century old. (Watch the disassembly below)

Read more about testing steel

Testing for wrought iron

Forging the Blade from Reclaimed Steel

The elemental simplicity of a brick charcoal forge supplied with air from a hand powered wooden fuigo box bellows forms the starting place for the shaping of a blade.
Most of the shaping can be done with well-placed blows from a hand hammer. Accurate forging makes the quickest and most efficient use of an entire piece of reclaimed steel.
A well forged piece is very close to its final size and saves time and waste when hand filing to final shape. A sen scraper and files are used to refine and true the form. (Watch some forging below)

Read more about forging a tanto

Forging a sunnobi tanto

Hardening & Tempering the Blade

The traditional yaki-ire hardening method using natural clay, charcoal, and rainwater can be risky but produces a hard cutting edge and a tough spine within a single piece of carbon steel.
After the clay layer has dried, the blade is slowly heated to the colour of the august moon and then plunged into water. The exposed edge cools more quickly and forms a very hard steel structure.
The body and spine of the blade cool more slowly and form a very tough steel structure. The rough stone finish on this blade reveals the temper line between the two areas. (Watch yaki-ire below)

Read more about yaki-ire

On classical tanto geometry

Making the Fittings

Reclaimed copper from electrical bus bars is very pure and forges well. Other materials include wrought iron salvaged from the sea, reclaimed brass door plate, and scrap copper water pipe.
Because the entire knife is held together with a single bamboo peg in the style of classical tanto, each metal and wood component must fit accurately on the tang of the blade.
The copper components are allowed to develop a fire patina or given a traditional rokusho style patina and then finished with buffed ibota wax or tung nut oil. (Watch making a habaki below)

Read more about making habaki

Making koshirae mountings

Making the Handle & Scabbard

The inside of handle and scabbard must fit the tang and blade precisely before the halves can be joined together with sokui (traditional rice paste glue).
Once the halves are rejoined, shaping and finishing the exterior of the Hounoki core is done with Japanese hand saws, planes, chisels, rasps, and kiridashi knives.
Each component is carefully carved, shaped, and fit together to provide strength and make best use of the natural properties of each material. (Watch a tanto mounting being carved below)

Read about carving a handle

Carving a tanto scabbard

Lacquering with Natural Tree Urushi

The first layers of urushi lacquer are applied thinly and wiped off to seal the wood until fully cured. Each layer is cured for several days and then polished before the next is applied.
For an ishimeji stone finish, crushed dried tea leaves are sprinkled into the wet urushi. After curing for several days, the tea leaves are sealed and strengthened with more lacquer.
Once the lacquer has fully cured, the fixed components are attached using kusune (pine resin glue) or a mixture of urushi and sokui, called nori-urushi. (Watch a tanto being lacquered below)

Carving and lacquering a scabbard

Learn about sokui.

Polishing & Final Assembly

A full tanto mounting may contain ten or more parts made from twenty or more components. Most of the parts are fit together only by friction and locked in place by the bamboo peg.
The major components of handle and scabbard are assembled. A combination of wood, rawhide, and tightly wrapped leather or cord strengthens the handle assembly.
Once all of the fittings have been built, the blade is given its final polish using fine natural Japanese waterstones and finger stones. (Watch a tanto being assembled below)

Read about water stone polishing

Aesthetics of the tanto form

Detailed Topical Articles for Students of the Forge

Assembly & Construction

Read about water stone polishing

How to open shirasaya

“Materials are the most perfect medium for the experience which shall illuminate the soul and ripen the mind: for they oppose your effort, and against that

beneficent and lovely resistance

you work out your ideas, with patience, with forethought, with skill, with pride, with self-revelation.”

– Edward Yeomans, Shackled Youth, 1921