Process of Carving & Shaping a Tanto Saya

Once the tsuka is made, it is time to create a saya (scabbard) for the blade. The saya should fit snugly on the habaki, with most pressure to the top and bottom, and should hold the blade securely without rattling or jamming. The lines and proportions must be appropriate to the blade and handle and take into account the appearance of the whole unit.

Similar to the process for tsuka, a saya is shaped in two distinct stages, first the wood is split and the inside carved to receive the tang, and then it is joined back together and the outside is carved, planed, and shaped. As with the tsuka, the lower part of the blade is placed slightly off centre in the block so that the edge is fully supported by wood rather than resting against the glue joint.


Carving the Inside

Creating a saya is begun by selecting an appropriate block of wood, sawing or splitting it into halves, and carving out each half to guide the blade smoothly. Carving is done with purpose designed chisels called saya-nomi (鞘鑿). The mune should be centered in the block of wood but the small flat surface for the edge should be fully seated in the omote half of the wood, slightly to one side. The purpose of this is to align the wood with the tsuka and keep the edge from splitting the glue joint if it ever makes contact with the saya. When the fit is just right and the blade sits in place, the two pieces of wood are joined back together with sokui (rice paste glue), and the handle carved and shaped once dry.

Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
A scrap block of Nootka Cypress with straight, clear, and relatively tight grain is split to align the woodgrain with the centre of the saya.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
The two halves are hand planed flat on the inside until they align tightly together again.
Island Blacksmith: Hand forged kotanto made from reclaimed and natural materials
The omote half is carved first, starting from the spine and moving across to the edge. The edge sits against the inside of this half fully which puts any potential stress against wood rather than against the glue joint.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
The ura side is carved next, checking the fit constantly. The edge just floats on this half. Note the oil reservoir in the tip of the omote side to collect excess oil and pull it away from the blade during storage.
Island Blacksmith: Hand forged kotanto made from reclaimed and natural materials
The blade space is carved first and then the habaki area is opened up. The last third of the habaki should engage and grip the wood, mostly on the top and bottom rather than the sides. Final adjustments take some time to get right.
Island Blacksmith: Hand forged kotanto made from reclaimed and natural materials
The two halves ready to be glued back together with sokui, a paste glue made from rice.
Island Blacksmith: Hand forged kotanto made from reclaimed and natural materials
Wrapped with a leather strap to provide tension, wooden wedges increase pressure where necessary. Note the way the edge is tilted slightly into the omote half of the block.

Shaping the Saya

The outside work is carried out using chisels, planes, and occasionally coarse files. The block is first squared up and then taken down to the rough dimensions. The shape of the koi-guchi (saya opening) is marked and carved and then the rest of the block is chiseled down to meet it. A plane is used to smooth and true up the surface and final sanding is done with tokusa (horsetail plant, equisetum hyemale, 砥草, “to” as in togi) glued to wooden blocks with sokui (rice paste glue).

Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
After the sokui is dry, the block is squared up to the blade opening using a tracing of the seppa in place on the tang as a template.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
A chisel or knife is used to carve the koiguchi down to meet the outline.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
Working with Nootka Cypress is a lovely experience. It carves well, planes smoothly, feels like silk, smells like spice, and the shavings look like spun gold.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
The rest of the saya is planed down, at first roughly to eight sides.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
The corners are removed repeatedly until the final shape is achieved.
Island Blacksmith: Hand forged kotanto made from reclaimed and natural materials
The koiguchi, shaped and marked for carving the shoulder to fit the horn reinforcement.
Island Blacksmith: Hand forged kotanto made from reclaimed and natural materials
Tokusa sanding blocks can be made in all sizes and shapes. Tokusa gives a finish that is a cross between fine sanding and burnishing, but does not leave grit as sandpaper can.

Horn Koiguchi

Often horn or metal reinforcements are added to the koiguchi to counteract the pressure of the habaki. The method for the koiguchi is to carve away enough wood for the horn or metal to sit in its place. The habaki is used as a rough guide for making the opening in the horn, a kiri used to drill holes and then files to create the shape of the guchi. Horn is tough but not as hard as bone or metal. It can be carved with chisels or knives and has a grain-like structure to it. Depending on the design, sokui (rice glue) or kusune (pine resin glue), or a mixture of sokui and urushi (lacquer) is used to fix it in place.

Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
In the 80’s every tourist stop gas station gift shop had these pairs of buffalo (or possibly even bison) horns mounted on hardwood bases and incised with maple leaves and the word, “Canada”. This pair came from a secondhand shop.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
The wood is carved away where the horn koiguchi will sit, this is a patience building activity.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
The opening is carefully filed until it just slips over the wooden shoulder on the saya.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
A chisel and scraper are used to dish the horn slightly down to meet the edge of the wood, ensuring a tight fit at the mouth.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
Rough shaped using the seppa and the saya to trace the outline on each side.
Island Blacksmith: Hand forged kotanto made from reclaimed and natural materials
The recycled souvenir koiguchi ready for polishing and installation with an urushi and rice glue mixture.
Island Blacksmith: Hand forged kotanto made from reclaimed and natural materials
Koiguchi sitting in place, polished inside, and ready for some final shaping and sanding outside.

Horn Kojiri

Often horn or metal reinforcements are added to the end of the saya to protect from bumps and dings. Horn is tough but not as hard as bone or metal. It can be carved with chisels or knives and has a grain-like structure to it. Depending on the design, a square tenon or wedge is used in conjunction with sokui (rice glue) or kusune (pine resin glue), or a mixture of sokui and urushi (lacquer) to fix the kojiri in place.

Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
A thicker piece farther up the horn will become the kojiri to protect the end of the saya. Sawed out and filed to approximate shape.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
The bamboo pegs give some additional stability against lateral bumps, another method is to use wedged horn or wood tenons.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
My old friend the leather strap doing some tricky clamping overnight.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
Kojiri in place, ready for some final rough filing to bring the edge more closely in line with the saya shape.

Wrought Iron Kurikata

Kurikata translates “chestnut shape” and in its basic form is the tying off point for the sageo (cord) that attaches the saya to the obi (sash/belt) so it stays in place on a draw. They are often made of metal or horn, and sometimes wood depending on the type of knife. A friend of mine dives 50′ down holding his breath, sometimes he brings back old iron he finds in the ocean. This old piece of wrought iron has a nice low-res grain to it so i used it as a compliment to the wrought iron tsuba (guard)by forging a kurikata from it.

Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
Here is the chunk of wrought iron as found, you can usually spot wrought/bloomery iron in the wild as it corrodes into a wood grain pattern. Modern mild steel rusts into a cratered moon surface rather than linearly.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
Rough forging to shape to get the layers to flow with the top of the finished piece, wrought iron needs to be worked quite a bit hotter than mild steel or it will split along its slag layers.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
The opening drilled, cold chiseled, and filed, and then the outside is shaped with a hacksaw and coarse files.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
A hacksaw is used to cut the workpiece off the main rod before finishing the other side.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
Drawfiling gives a good base surface for the oxidizing process. Using a little chalk on the file helps keep the gummy wrought iron from clogging the teeth and galling the workpiece.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
The shape is adjusted slightly by forging and then high heat and strong air blast are used to get the surface to oxidize and reveal the natural grain structure. This process is called yakite or yakinamashi, one case where the smith wants heavy scaling to occur! Between heats it is quickly dipped in water and cleaned with a wire brush to expose new iron to the fire and air, repeating as necessary.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
Fresh out of the fire, the grey surface and deep tekkotsu are a nice improvement over the shiny filed surface. It will be soaked in vinegar and water over night to remove the fire scale and then brushed clean.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
Because of its tapered shape and slightly curved bottom, the kurikata can be tightly mounted in a keyway in the saya. A fine saw and small chisel are used to create and adjust the channel.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
A few taps with a wooden mallet sets the kurikata tightly home as the curved bottom lifts it up into place.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
The finished and installed kurikata, formed of wrought iron from the sea. The shapes and lines of this one remind me of the westcoast…

Shitaji, Preparing the Foundation

There are two distinct stages to using urushi (traditional Japanese lacquer, made from the sap of a tree). The first stage is to prepare the base material by sealing, filling, and polishing, and the second is to coat with a smooth finishing layer. Urushi is used in several ways to prepare the surface, first by coating and wiping off, known as fukiurushi, and also as an adhesive and gap filler when blended with other materials such as sokui (rice glue) and finely powdered clay and earth.

Each time a layer is added to the foundation, a minimum of one day is required for curing, and then the surface is wet polished and dried before adding the next. The goal is to seal the surface and fill in any low spots so the final layers of urushi goes onto a smooth and even surface.

Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
Using a thin wooden spatula the saya is coated with a thin layer of ki-urushi. After soaking a few minutes it is wiped off with a sturdy cotton cloth. Raw urushi looks like light chocolate milk but it immediately begins to oxidize to a darker and darker colour as it sits out.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
After about four hours the colour is a reddish chocolate. The next day it has cured enough to handle and add the next layer.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
A putty is made from roughly equal parts ki-urushi, and sokui (rice glue), and a double measure of very finely ground clay. In this case the only areas that need this kind of gap filler are along the edges of the horn koiguchi and kojiri and around the kurikata. A thin wooden spatula is used to work it into the gaps and remove the excess.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
Two days later, the excess is carefully and sparingly sanded down with wet 400 mesh paper. When fully dry, another layer of fukiurushi is always applied (wiped off with cotton cloth) to saturate the jinoko or sabi layer.

Urushi, The Final Layers

There are several approaches to applying the final layer, depending on the desired finish and the style and skill of the artisan. One is to paint the last layer thicker than the foundation and middle layers and allow the urushi to settle out into a glossy surface. The other is to polish the brushed layer and then apply several coats of fukiurushi followed by a fine oil polish.

Each time a layer is added to the surface, a minimum of one to two days is required for curing, and then the surface is wet polished and dried before adding the next. The saya is placed in a warm and humid place, kept as dust free as possible, to ensure the urushi will cure properly.

Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
Two layers of raw (natural colour) followed by a layer of half natural and half black, and then two layers of black. Each is applied, cured, and wet sanded with 1200 mesh paper. During the process, the black is selectively sanded through to reveal the natural urushi layers in areas of natural wear.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
The final layer of black is wet polished with charcoal and 1200 mesh paper.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
Several coats of black fukiurushi are applied to the saya and allowed to cure in the furo for a day or two each. In the bright direct sunlight, the worn and cared for negoro inspired look is quite apparent, but under normal viewing conditions the surface is far more subtle and has a dark chocolate colour and tortoise shell appearance. The finishing touch will be a thin coat of 100% pure tung oil.
Island Blacksmith: Hand forged tanto made from reclaimed and natural materials
An alternative finish involves embedding fine particles of charcoal, dried lacquer, or iron into the second layer of urushi. When it is dry, the excess powder is removed and then several thin coats of urushi are wiped on and dried for 24-48 hours each. The finished surface, called ishime-ji, gives the appearance of matte stone texture and is fairly hard wearing as minor scuffs are hidden by the pebbled texture.

The next step in the process is The Final Polish and then Final Assembly.