Shiage Togi: A Guide to Finish Polishing in Japanese Swords
Shiage togi or finish polishing the last half in Japanese sword polishing. It is performed by a professional sword polisher (togishi) using various polishing stones and techniques after shitaji togi or foundation polishing.
This article delves into finish polishing, the tools or items required, and the steps involved throughout the process.
Note that the first half of the Japanese sword polishing process is covered in another article, “Shitaji Togi: A guide to Foundation Polishing in Japanese Swords”.
A Brief Overview of Shiage Togi
Since shiage togi completes the sword polishing process, it is also known as finish polishing. The same principles in shitaji togi applies here:
- Great control and precision
- Awareness of blade and stone contact
- Paying special attention to the blade’s ridgeline.
However, there are some significant differences compared to the first half:
|Shitaji Togi (Foundation)
|Larger and coarser
|Blade is moved over the polishing stone.
|Shiage Togi (Finish)
|Thin and shaved, backed with paper and lacquer
|Blade remains stationary while stones are moved over the blade.
The aim of shiage togi is to bring out the fine details of the hamon and the steel. This includes the effects of differential hardening such as the nie and nioi (large crystals and fine particles). All these details are crucial in giving the blade its identity and represents the togishi’s skill.
While a good polishing reveals and enhances all the details of the blade, a poor polishing will cloud them, decreasing the sword’s value and doing a disservice to the swordsmith.
Steps in Shiage Togi
The following steps and processes are the major ones in shiage togi and are therefore, not exhaustive. In practice, a togishi may have additional or different steps depending on their school or individual style.
While hazuya stones are available for purchase, some togishi opt to make their own as Hazuya stones are essentially thin uchigumori wafers.
Making Hazuya Stones
To make Hazuya stones, cut pieces 0.25 – 0.33 inches (0.64 – 0.84 cm) thick from an uchigumori stone. Grind the pieces on a rough sandstone to give it a uniformed thickness about 1/16 inch (0.157 cm).
Next, they are polished on a finer stone for a smooth surface. One side of the hazuya is first coated with urushi (lacquer). Then, a piece of yoshino gami (porous Japanese paper) is applied and another coat of lacquer added.
Once dry, grind the pieces further and cut them into several small squares with each side about 0.5 – 1.0 inch (1.27 – 2.54 cm). The edges are rounded off to make sure the hazuya are smooth and thin, roughly 0.005 inch (0.013 cm).
Once the hazuya stones are ready, other items required are:
- Tojiru – A thin lubricating paste made by rubbing two wet uchigumori stones together.
- Water – Sodium carbonate is added in the water so it is alkaline to prevent the blade’s wet surface from rusting.
Polishing begins by applying a small amount of tojiru (a thin lubricating paste) and water onto an area of the blade that will be polished. The blade is then placed on a stand and held steady using the left hand.
With the right index and middle finger curled into a fist, it is placed against the blade to serve as a guide during the process. The hazuya is held between the right thumb and blade. It is then moved back and forth lengthwise along the blade, one section at a time.
Hazuya polishing starts at the tang’s ridgeline down to the edge, gradually moving towards the point. Note that the point is not polished at this stage. If foundation polishing steps were done well, hazuya polishing will significantly take less time.
- Function – Remove uchigumori marks
- No marks or blemishes in the hamon or steel
- Smooth and uniform blade surface
- Blade has a whitish and cloudy appearance
The orange or yellowish brown Jizuya stones are made by chiseling flakes from a narutaki stone. It is similar to uchigumori, but harder and finer. Like the Hazuya stones, grind the flakes and back them with paper and lacquer.
There is much variation in the hardness of the stones at this stage. Based on preference, vision, and experience, the togishi chooses the grade of jizuya to use. This will affect the blade’s final texture, color, and steel detail.
Jizuya stones are used in the same way when polishing as Hazuya stones.
- Function – To bring out the shinogi-ji and ji
- Blade becomes clearer and darker
- Jihada begins to stand out
Nugui is a fine suspension of iron oxide particles in clove oil that functions as a very fine abrasive. While it can be bought, some togishi prefer to make their own.
When steel is heated to a high temperature causing it to turn yellow or red, a layer of iron oxide forms on the surface. This layer peels off easily when the steel is struck with a hammer. The flakes from the layer are then collected and ground into a fine powder, known as kanahada.
After mixing kanahada with vegetable oil, the mixture is strained through several layers of paper (yoshino gami) to filter out larger particles that can scratch the blade, producing nugui.
This final step in surface polishing entails applying a small amount of nugui to the blade and rubbing it in with cotton. This is done section by section, one to three times over the entire blade. Note that it is not used on the point area.
- Slight polishing
- Cosmetic purposes – Darkening and highlighting parts of the blade
- Darkened steel – Too much nugui turns the metal black
- Non reflective finish
- Highlights surface details and metal grain
Since a prominent white hamon is often favored today even by NBTHK judges, hadori is often performed to produce a contrasting edge. This is performed using a hazuya stone cut into an oval shape to remove any sharp corners that can scratch the blade.
Hadori polishing begins at the hardened edge near the tang. After applying some tojiru, the oval hazuya stone follows the hamon along the edge up to the point.
Since the hazuya stone is coarser than the jizuya stone and nugui mixture, it results in larger scratches. This means hadori polishing results in an area that appears whiter than the rest of the blade. This is a time consuming step and can take up to two days to complete.
Note that while a white hamon is preferred, it can mask some of the finer details of the blade. Therefore, collectors who focus on metalwork and craftsmanship prefer to omit hadori and use sashikomi polishing instead to emphasize the details of the hamon.
- Causes deeper scratches than jizuya and nugui
- Lighten the appearance of the hamon
- Hamon is whitened, causing its appearance to be enhanced as it contrasts against the darker nugui finish applied previously.
Kissaki no Narume
During foundation polishing, the point area is moved perpendicularly over the stones. In shiage togi, kissaki no narume or polishing the point is left till much later, skipping hazuya, jizuya, and nugui.
Making the Yokote
The point area is divided from the rest of the blade by the yokote, a straight line running across the blade to the edge. There can be an actual ridge or just a visual demarcation. If there is no such line, it is up to the togishi to make one.
Before polishing the point, the rest of the blade is wrapped for protection. Functioning as a guide, a flat piece of bamboo (mask) is positioned on the blade in a way where its edge will become the yokote.
With the mask held in place, the blade is laid on a flat work surface. Tojiru is applied and a small piece of hazuya is placed flushed against the mask’s edge. Next, a bamboo spatula holding the hazuya is moved back and forth along the edge of the mask.
The section of the point area polished with hazuya is then whiter than the rest of the surface, resulting in a clear and sharp yokote.
A narume dai is a wooden block around 1 inch (2.54 cm) wide and 10 inches (25.4 cm) long with several sections removed to make the top surface springy. Soft Japanese paper is folded 8 to 10 layers as wide as the block, wet thoroughly, and placed on the block. A large thin piece of hazuya stone follows.
While the narume dai supports and cushions the hazuya, the wet paper allows the stone to move according to the pressure the togishi exerts on the sword. This is important as the point area is rounded and a hard stone would not make contact with the whole surface.
A fumaegi (curved piece of wood with a hooked end that clamps the polishing stone to the work block) will also be required.
Polishing the Rest of the Point
Once ready, the narume dai is held in place with the right heel on the fumaegi. The point area is then moved from the yokote to the tip over the hazuya perpendicular to the blade’s length.
- Polishing the tip of the blade
- Boshi (tip area’s temper line) is whitened, clear, and has a matte finish, allowing it to stand out from the rest of the blade.
- Yokote is at the proper angle in relation to the back and edge of the blade.
Shiage togi is complete after migaki or burnishing of the mune (back of the blade) and shinogi ji (surface of the blade between the back and ridgeline). Burnishing compacts the steel with pressure, creating a bright and reflective surface.
Burnishing Preparations & Tools
Before burnishing, the relevant surfaces are prepared by cleaning them with tsunoko paste, a mixture of powdered horn and water.
After it dries, it is dusted with ibota, a fine lubricating powder made from an insect’s (Ericerus pela) waxy excretion to help the burnishing tools move across the surfaces smoothly.
For the process, migaki bera (burnishing spatulas) and migaki bo (burnishing needles) will also be required. These items are made of extremely hard steel and can come in different shapes and sizes.
Burnishing the Surfaces
The burnishing spatula is used before finishing using the needle. Both are rubbed briskly over the surfaces until there is an even mirror-like finish. Bamboo pieces or masks may be used to prevent the needle from slipping into areas that should not be burnished.
Burnishing starts near the tang up to the blade, around 1.5 inches (3 – 4 cm) at a time.
- To create a decorative contrast between the mune and shinogi ji with the rest of the blade.
- To polish the inner surface of grooves.
The blade’s shinogi ji and mune have a bright and mirror-like reflective surface, contrasting with the other areas of the blade.
Summary of Shiage Togi Steps
|► Remarks: Made from uchigumori stones
► Function: Remove marks from foundation polishing
► Results: Blade has a smooth and uniform whitish and cloudy appearance without any marks or blemishes
|► Remarks: Made from narutaki stone
► Function: To bring out the shinogi ji and ji
► Results: Clearer and darker blade with distinct jihada
|► Remarks: Made from fine iron oxide particles (kanahada) mixed with clove oil
► Function: Slight polishing and to give the blade a darker and more uniform finish
► Results: Darkened blade with a non reflective finish that highlights surface details and metal grain
|► Remarks: Uses hazuya stones
► Function: Cause deeper scratches on the hamon, lightening its appearance
► Results: Enhanced whitened hamon contrasting against darker nugui finish
|Yokote suji kiri
|► Remarks: Uses a mask (bamboo or tape), bamboo spatula, and hazuya stones
► Function: To make the yokote line
► Results: Yokote is made at proper angle in relation the the edge and back of the blade
|► Remarks: Uses narume dai, washi paper, hazuya stones
► Function: To polish the point area
► Results: Clear and whitened boshi has a matte finish, standing out from the rest of the blade
|► Remarks: Uses migaki bera (burnishing spatula) and migaki bo (burnishing needle)
► Function: Create contrast for the shinogi ji and mune
► Results: Bright and mirror-like shinogi ji and mune contrasts with the rest of the blade
The Final Result
After both foundation and finishing polishing, the togishi’s job is complete. The polished blade will feature clean and well defined lines with a clear and even finish. The various details on the blade are brought out including the:
- Distinct grain
- Surface textures
- Prominent hamon
- Delineated yokote
- Finished point
- Contrasting surfaces