Tools for Satoyama - Making the Mountain Tanto

[DaveJ]

this is the tanto-sized version of the mountain kotanto pattern...

 

 

Satoyama are the managed forest areas that border the cultivated fields and the mountain wilds in Japan. Historically they provided fertilizer, firewood, edible plants, mushrooms, fish, and game, and supported local industries such as farming, construction, and charcoal making. Balancing the interaction of wetlands, streams, forests, and fields is an important component of the satoyama landscape and allows for sustainable use of the rich resources they offer.

 

 

About the Tools for Satoyama Project (more: islandblacksmith.ca/2016/03/tools-for-satoyama)

 

The Tools for Satoyama project is inspired by this mutually beneficial interaction between humans and the natural world, a robust way of life that sustained both for centuries. Among the goals of the project are contributing to the growing awareness of the satoyama concept, sustainable practices, thoughtful approaches to intentional living, and related historical learning.

 

The four styles of kotanto knives designed for the project are named for the four main areas found within the satoyama landscape: stream, field, forest, and mountain. In addition, the forest and mountain models also come in a full sized tanto configuration. Some of the core characteristics of the knives produced for this project are the reclaimed and natural source materials, use of traditional techniques, and a humble and simple style of carving and finishing.

 

About the Mountain Tanto (more: islandblacksmith.ca/2016/04/making-a-mountain-tanto)

 

The wider profile of the mountain style tanto is inspired by a kamakura sword and has a more deeply curved tip (fukura-tsuku) and shorter drop point. The simple and humble mounting style is inspired by the age-old style of farming and foresting tools traditionally used in managing satoyama lands.

 

Project Overview Video

 

[DaveJ]

Forging & Hardening Blade

 

A worn out and rusted file serves as the starting material for the blade.

 

 

A charcoal forge provides the heat to hand forge the file into the shape of a tanto blade.

 

 

After forging is complete, the profile is cleaned up with a file. The surface of the blade will retain its hammer texture and the pattern from the original file teeth.

 

 

A sen dai style staple vise holds the blade while filing the bevels closer to finished dimensions.

 

 

A mixture of natural clay, charcoal, and polishing stone powder forms an insulation layer for hardening.

 

 

The clay is slowly dried over the charcoal fire. Note the recurve in the edge to compensate for the upward pull during yaki-ire style hardening.

 

 

After yaki-ire, the remaining clay layer is scraped off to reveal the newborn blade.

[DaveJ]

Forging & Fitting the Guard


The guard is forged from one quarter of a silver-plated copper bus bar washer. The round hole is forged down into the narrow hole for the tang.



The opening (nakago ana) is adjusted by filing until it slips into place on the shoulders of the blade (machi).

[DaveJ]

Carving the Handle & Scabbard (more: islandblacksmith.ca/2016/02/making-a-tanto-takedown-handle)

 

The tools used for creating this style of handle are quite simple, the work can be done with only a handsaw, a saya-nomi chisel, and a kiridashi knife. A wood block kanna plane is also helpful for leveling the inside and shaping the outside.

 

The core of a handle and scabbard are traditionally carved from hou-no-ki (Japanese Bigleaf Magnolia) due to its non-acidic, moisture-stable, and shock absorbing nature. The example below was carved from local Nootka Cypress which shares similar grain density, moisture stability, and shock absorbing properties.

 

The glue for rejoining the halves is rice paste glue (sokui) which is non-acidic and does not gum up cutting tools when working. The simple clamping system uses a leather strap and scrap wedges of softwood to tension the halves while the glue dries.

 

Proper geometry of the tang is crucial to making a properly functioning nihonto style takedown handle. The tang must taper in thickness and width from the machi (blade shoulders) along the spine, and the edge side should be an even thickness of about 2mm all the way from the machi to the tip of the tang. The surface should be relatively smooth and even, with no major bulges or dips, and it goes without saying that the blade must always be hardened and tempered before starting work on any fittings. Read more about tanto geometry here: Classical Tanto Geometry Archives

 

The blade in the example below was forged from a reclaimed file and will have a forged final finish in the Tools for Satoyama style. If it were to be polished, the final geometry and dimensions must be set first, but the final polish and sharpening are done after the handle has been made.

 

If it were to have a habaki and seppa, these would also be made before fitting the tsuba (guard) and carving the handle, to account for the difference in length. I don't recommend skipping the habaki in a large knife's construction as it is more difficult to achieve and maintain a good fit to the scabbard, but it can be done. The blade here is just under 7.5" long, the tang about 4", and the spine at the munemachi is about 5mm thick.

 

Some Parameters

 

The knife has two sides with unique names, the omote and the ura. The omote is the "public side" and the ura is the "private side". When worn with the edge up and the handle towards the right hand, the side facing outwards is the omote and the side facing against the body is the ura.

 

The tang does not sit halfway into each half of the handle, the split line is slightly to the ura side making the omote block slightly larger. This offset only occurs on the edge of the tang, the spine is evenly split. The purpose for this is to place the stress along the edge against wood rather than against a glued joint. This is far easier to understand than to explain in words, see below.

 

When the halves of the handle block are held together, it becomes apparent that the split runs slightly diagonally through the centre of the spine and along the ura side of the edge. This provides a strong "shelf" of wood for the edge of the tang to rest against. (Ura on the right, omote on the left)

 

 

Splitting the Block

 

The grain should run as straight along the handle as possible to give strength to the handle. Also, for the sake of stability, many historical examples run the growth rings diagonally across between omote and ura when viewed from the ends.

 

If the block is large enough, one need not worry about making the split slightly diagonal, simply split down the centre and trim off the excess later on. A sharp handsaw will split fairly straight and a kanna plane can be used to true up any wobbles or tooth marks. The halves must fit together flat and true with no gaps or rounding. It is wise to mark the blocks so there will be no mistake in placing them back together the same way again whilst working.

 

When possible, the handle and scabbard are cut from the same block. The inside surfaces are planed as flat and level as possible to provide a tight joint.

 

 

Carving the Omote

 

The omote side is carved first and has the deeper carving work to be done on it. The blade and fittings are placed squarely and snugly against the front of the block and the tang traced. Then a kiridashi is used to cut a shallow line around the exact location of the edges of the tang. Carving up to the scored line, the mune is cut and then then working across the edge of the tang is cut.

 

The depth of the spine side should be half and the edge side should be flush but not inset at all. Careful carving will ensure the tang is contacting wood all around without any gaps. Sliding the tang into place will burnish any high spots enough that they can be seen when viewed obliquely into a North window. Working slowly and checking often will save wood and time.

 

The spine is split down the middle and as it tapers the depth decreases. At this point the fit is snug enough to support its own weight by friction.

 

 

The edge is fully encased in the omote side half.

 

 

The fit around the tang is quite snug, including against the guard, and there is a small reservoir cut in at the tip to accommodate adjustment and settling if need be.

 

 

A view of the end of the tang seated in the omote side half.

 

 

Carving the Ura

 

The ura side is carved after the omote is fairly close to final dimensions, though often a small amount of readjustment is necessary once both are carved. Aligning the tang for tracing is more difficult this time around and care should be exercised. Holding the blocks together and marking where the omote side opening is located is helpful. This time the kiridashi cut is only made along the spine as the edge side will not be notched in at all.

 

Carving from the mune and working across to the flush edge side, frequent checking and restraint are required. When the dimensions are close, testing with both halves held together may reveal additional areas for adjustment. The goal is for all surfaces to be smooth and the tang to seat snugly but still removable.

 

The spine side of the ura half should be a mirror of the omote half.

 

 

A view of the fully exposed tang edge of the ura side half.

 

 

The ura (left) and the omote (right) carved to fit and ready for joining.

 

 

Rejoining the Halves

 

Rice paste glue (sokui) is used to join the halves together as it is non-acidic and kind to wood carving tools when dry. A paste of mashed rice and a few drops of water is applied thinly to both halves and placed together lightly and reopened to check the contact points. If any area is missing sokui, more can be added or redistributed and if any is pushed out into the tang area it must be fully removed.

 

The glued halves are joined and then clamped with a leather strong lace. Winding too far apart will place a diagonal pull on the blocks and they may slip. Thin wedges of softwood are placed under the wrap to further tighten and prevent slipping. The glue is allowed to dry for 24 hours before unwrapping.

 

The handle is joined with rice paste glue (sokui) and then wrapped in a leather lace and wedged tightly until dry.

 

 

The alignment is checked while wrapping and wedging to prevent any movement.

 

 

 

Carving the Exterior

 

Once the blocks are dried, the exterior is carved to shape using chisels, a kanna plane, and kiridashi knives. Tracing the location of the tang on the sides as well as the fittings on the end gives reference points for planning the handle shape.

 

Often the first shaping step is to use a plane to square the block up to the blade if it is angled or off-centre. After this, a kiridashi or chisel is used to carve the outline of the handle cross section first at the end and then the rest of the block is carved down to meet it.

 

Carving the exterior should be based on the location of the fittings and the tang, as well as the blade's relation to the handle.

 

 

Once the shape and size of the end is established, the rest can be planed down to meet it and then the details shaped with a kiridashi or chisel.

 

Carving the Scabbard

 

The scabbard is carved inside and rejoined with rice paste glue (sokui).

 

 

Once the blocks are dried, the exterior is carved to shape using chisels, a kanna plane, and kiridashi knives.

Edited September 8, 2016 by DaveJ

[DaveJ]

Lacquering the Handle & Scabbard

 

The first layers of natural urushi lacquer are applied to seal the surface of the wood and the cord wrapping. Additional layers will strengthen and provide the ishimeji (stone surface) texture when mixed with crushed and dried tea leaves. More on these techniques: https://www.youtube.com/watch?v=dGVCgaF7IYA

 

 

The finished Tools for Satoyama Mountain Tanto disassembled into its component parts.

 

 

 

 

Specifications

 

The blade is just under 7.5" long and the overall length is about 12". The spine at the munemachi is about 5mm thick.

 

Nagasa (blade length): 187mm

Motokasane (blade thickness): 5mm

Motohaba (blade width): 29mm

Sori (curve): uchizori

Nakago (tang): 109mm

Tsuka (handle): 112mm

Koshirae (overall): 340mm

 

Katachi (geometry): hira-zukuri, iori-mune

Hamon (edge pattern): suguha

Boshi (tip pattern): maru

Nakago (tang): futsu, kuri-jiri, one mekugi-ana, signed near the tip

Mei (signature): hot stamped katabami-ken kamon

Koshirae (mounting): satoyama chisagatana style, issaku

 

yoroshiku!

[JDWare]

very, very beautiful work... thanks for documenting it so well and sharing it

J

 

JDWARE KNIVES

[Nick Woo]

Great to see you on here as well as youtube. Love all the photos. I love the texture of the saya.

Edited September 9, 2016 by Nick Woo

[Jan Ysselstein]

Another great tutorial Dave...thank you

[DaveJ]

much appreciated, gentlemen!

[Lukas MG]

I love your posts. Other than doing great work you do some kick-ass photography as well.

[Adam Weller]

Absolutely love these. Beautiful knives and I really appreciate the presentation and process, overall stunning!

 

Forgive my naivety as I am still very new to the craft (and know nothing of Japanese traditions), but I was hoping you could speak to the process of pinning the handle (placement of the mekugi). I can see you drill after the heat treat and after you have carved the handle shape. Do you drill the Tsuka first, then mark and drill the Nakago next? How do you ensure a tight fit?

Thanks!

[DaveJ]

@aweller the normal process (as i have seen it with shirasaya) is to put the hole in the tang first, then to mark it on the outside of the tsuka but lining up the habaki, etc, and then to drill through the tsuka while the tang is in the handle which allows the tang to guide the kiri to stay within the right location, then a round file enlarges the hole to final size...

 

in this case because there is a lacquered cord wrap i wanted to have the tsuka hole quite accurate first so i could lacquer the cord in place and re-open it later when cured...not recommending it but it is possible to do that way...so i marked the tang and drilled and filed it to match the tsuka (the tang needs to come out for filing or you will inadvertently enlarge the tsuka as you go)...

 

getting a tight fit of any of these components is mostly a matter of going very slowly and checking 10x more than you think it necessary ^___^

[Dan Rice]

Pardon the thread necromancy, but where can I find more information on this rustic style of tanto?  I've been wanting to make a more or less authentic tanto for a long time, but I've been intimidated by the habaki and wrapped handles.  I was thrilled to find that there is an authentic no-frills version.  Is there anywhere online that I can find some pictures of historical examples that I could get some ideas from?  I tried googling it but all I found was your knives, lol.

[DaveJ]

@Dan Rice that's all you will find, this is not a historical style but is my own project based on historical forms, materials, and techniques from other "genres", and the difference is mainly in the surface finishes...you can read most of the origins of the style and project in the first post or follow the links for the whole story...then you would research both classical tanto, their older counterparts in koshigatana, etc,  (markus sesko's koshirae book has some good examples) as well as japanese farming tools for more information on the components...there are plenty of historical alternatives to the ubiquitous silk wrapped handles for antique tanto, but habaki is definitely not a frill and really should be part of any nihonto-style mounting system larger than a few inches, keeping the scabbard secure long-term is quite difficult without the geometry they provide and they also stabilize and strengthen the whole system...

 

http://islandblacksmith.ca/tag/tanto-geometry/