An Introduction to Mishima
Mishima is a technique of inlaying slip, underglaze, or even contrasting clay into the main clay body of the pottery piece. This technique creates extremely fine, intricate design work with hard, sharp edges that can be difficult to reliably replicate in any other way.
Although this technique is known by the name Mishima, it is misleading. Mishima is a city in Japan. Although many Japanese pottery techniques are called after their city of origin or the family name of the first practitioners (i.e. raku), this is not the case with Mishima.
What we know as Mishima was first produced in Korea during the Koryo Period (CE 935–1392) and was further developed in the 12th and 13th-century Korean celadons. The term now used gained popularity as this type of pottery, introduced from Korea, as compared to the script used on calendars created at the shrine at Mishima.
Today, you can use this same technique to create exciting pottery and ceramic art that still feels fresh and modern. Creating a Mishima piece involves six steps: creating the pot, incising the design, filling the design, removing excess material, drying the piece, and firing.
Carve the Design
Both the clay and the slip (or underglaze or soft clay) should have fine particles without inclusions. Clay bodies with grog, sand, paper pulp, or other additives are not good candidates, as it will be much more difficult to get a smooth, flush surface when the excess material is removed.
Carve the Mishima Design
Carving a design is the first step in the Mishima technique. Generally speaking, it is easier to get cleaner lines when the clay is a medium to stiff leather-hard. However, this can cause problems as the clay body and inlay slip or underglaze have different moisture contents, which can cause cracking and poor adhesion between the two.
If you do allow the main clay body to stiffen first, slow the drying speed down considerably once the contrasting slip is applied. Cover the piece with plastic or place under a slightly raised bucket to help even out the moisture content and slow the drying.
If possible, carve the clay as soon as possible. As you can see in the example photograph, there are likely to be lifted edges and loose bits and pieces as you do this. Do not clean the piece up as you go.
As you incise or carve, keep in mind that you will be removing some of the surface clay as well as the excess slip. Make your incised lines deep enough that the inlaid design will not be erased during the clean-up process.
Tools for incised lines will depend on how you wish the piece to turn out. In the example, a mini-loop tool is used to remove clay, resulting in a thick-and-thin design reminiscent of calligraphy. Other line characteristics can be achieved by using other tools such as pencils, sgraffito tools, loop and ribbon tools, or small sticks.
Clean the Mishima Design
As you get more experienced with incising clay for Mishima, you may be able to incorporate cleanup of the design with the incising. However, if you are fairly new to this technique, it often works better to allow the raised excess to dry slightly before removing it. Since it has more surface area, it will dry faster than the main body of the pot or piece.
Generally speaking, you can clean up the incised design within half an hour to an hour. You do not want to wait any longer than you need to since you want the clay and the slip to bond.
The main concern during this step is keeping the incised edges as crisp as possible. Keep in mind that this will be seen as the edge between contrasting colors. Soft edges will result in wavering lines.
Remove all large bits using a potter's needle. To gently remove small pieces, use a very soft brush, such as a camel hair or bamboo brush, and gently sweep the surface of the clay. Use your wrist to flick the brush over small areas in a fast motion, but with the soft hairs of the brush barely touching the surface.
Apply Slip or Underglaze for Mishima
The next step to create a Mishima design is to inlay slip into the incised design. Generously apply the contrasting slip or underglaze to the pot. Remember that as the slip dries, it loses a lot of its volume. This means that if the slip is flush with the pot's surface when applied, it will become a sunken design as water evaporates out of it.
If you are using a single inlay color, you can simply spread a thick layer of slip over the entire surface. Broad brushes or sponge brushes are good for large areas, and smaller, soft brushes work well for small areas.
If you are using multiple colors in your Mishima design, carefully apply the slip to the appropriate areas. Use smaller brushes and be careful not to allow the slips to smear into each other.
As you apply the slip, be certain to push it down into all incised areas and lines. Air can easily get trapped below the slip if it is not forced out during the application, ruining the Mishima design.
Ready for Scraping
Allow the Mishima pot to become bone dry. The drier the pot was before you introduced the slip, the more slowly you should allow the slipped pot to dry. This will decrease the chance of cracking in the slip creating the design.
Once the pot or clay piece is completely dry, you may be able to see a ghost image of the incised design on the upper surface of the layer of slip. Do not rush to the next step until the piece is bone dry. Otherwise, chunks of the clay or slip will likely break out of the design.
When you're ready to scrape, several different tools can be used to remove the excess material fro the Mishima surface.
Control Clay Dust
In all cases, clay dust will be created. Clay dust is a serious irritant to the respiratory system and should not be inhaled.
- Use a high-quality dust mask or respirator.
- Work in a well-ventilated area.
- Clean up clay dust as quickly as possible. It is best to gather the dust and put it into water (e.g. bucket of clean-up water) at intervals as you work.
The blades of Stanley's Surform tools are well known as exceptional tools for shaping greenware. They can also be quite useful when making Mishima designs.
- It removes a large amount of material quickly
- It's very useful for creating flat surfaces
- It leaves ridged tool marks which must be removed with a different tool to achieve a flat surface
- It does not bend so is not useful for curved surfaces
- It is not suitable for small areas or for delicate designs that are not deeply inlaid
It's recommended for large flat surfaces as a preliminary tool. It's also useful to remove excess from large faceting on ware.
Loop Tool Used
Loop tools can be used to scrape off the excess material. Larger loop trimming tools are sturdier and tend to handle the pressure better. Hold the tool so it is at a shallow angle to the clay surface, then it draws toward yourself, moving in the same direction as the handle is pointed.
- It removes a relatively large amount of material fairly quickly.
- It's useful for both flat surfaces and those with gentle, broad curves.
- It allows you to get into any dips or depressions in the clay surface without taking material out of other areas.
- It can leave planes visible on the clay surface if care is not taken.
- It can be easy to take too much material too quickly if too much pressure is applied.
It's recommended for larger surfaces as both a preliminary tool, but also a touch-up tool for depressions in the main surface of the pot. Care must be to hold the tool so that the tool is only lifted slightly while working. Due to the pressure needed, this tool may work best with areas such as flay tiles, which can be completely supported on the other side. (Too much pressure will break the greenware.)
Thin, flexible metal ribs can also be used to remove excess material from the Mishima design. Use them held at an angle less than 45 degrees to the clay surface and draw toward you. Try to keep the rib from bending, as that distorts the scraping edge of the rib.
- It can remove a fair amount of excess material relatively quickly.
- With care, it can be useful for curved shapes.
- It is very easy to distort the shape of the rib, which can lead to uneven surfaces and disfigured pots.
- It is difficult to hold for any length of time.
- It is very easy to accidentally cut into the clay surface since the edge is so thin.
It is not recommended unless you have no real choice. There are easier, more reliable tools to use for excess material removal.
Paint scrapers can be quite useful when making Mishima designs on large pots or with flat tiles. Hold the scraper at a shallow angle to the clay surface and push it away from yourself. Do not apply undue pressure; let the blade do most of the work.
- It removes a large amount of material quickly.
- It is very useful for creating flat surfaces.
- It is great for use with Mishima tiles.
- The pottery surfaces must be well supported or be sturdy enough to handle the pressure involved.
- It does not bend so is not useful for curved surfaces.
It is recommended for large, heavy pieces with faceted or flat surfaces, or for greenware that can be fully supported on the other side of the clay surface. Not for use on delicate greenware.
Sandpaper is a useful tool when revealing Mishima designs. Use large pieces of sandpaper for large areas, and cut smaller pieces of sandpaper for smaller areas of Mishima or complex surfaces.
Coarse sandpaper removes more waste material faster but will leave scrape marks. Fine sandpaper will not remove much material at each stroke but will leave a smoother surface.
- It is useful for delicate designs, especially when using fine sandpaper.
- It is useful for curved and complex surfaces.
- Coarse sandpaper leaves scrape marks, which must be removed with a different tool or finer grade of sandpaper.
- It does not remove much material for each stroke and quickly gets clogged by waste material.
- There is a possibility of cutting into the clay surface, should the sandpaper edges catch onto it.
Although it can be used, sandpaper is not recommended due to the low amount of material removal and the scrape marks which are often left behind. There are better tools for Mishima.
Flat Plastic Scouring Pads
Mishima designs can be revealed by using flat plastic scouring pads. These pads are flexible and easy to use.
- It removes a fair amount of material per stroke.
- It is very useful for curved and complex surfaces.
- It will not clog as rapidly as sandpaper, and most clogs can easily be removed by simply thumping or slapping the pad.
- It may require support behind the clay surface if much pressure is applied while removing unwanted material.
- It does not work especially quickly, so can require a lot of effort if used on large pieces.
It is recommended for many Mishima applications, especially delicate and small to average-sized pieces. Because they do not have a hard edge the way sandpaper does, they will not inadvertently cut into clay nearly as easily.
Round Plastic Scouring Pads
You can also try out round plastic scouring pads.
- It does not clog with clay dust.
- It might be useful for very delicate but large pieces.
- It does not remove much material.
- It is hard to achieve fine control in what areas are being scoured.
It is not recommended for most Mishima applications. These may be helpful to remove small amounts of material from large areas.
Scour-pad sponges are another option.
- When used dry, it quickly becomes clogged with clay dust.
- When used wet, it smears clay and slip around while still not removing any material.
It is not recommended.
Mishima designs can be revealed using steel wool pads, such as those used in woodworking. Steel wool can be found in many department stores that have an automotive section. It comes in coarser (#2-#1), medium (#0-00), and finer (#000 to #0000) grades. Coarse steel wool removes a greater amount of material.
- It removes a large amount of material quickly.
- It is very useful for curved and complex surfaces.
- It is very versatile while still allowing a good deal of control.
- The coarse grade may leave marks, which must be removed with a finer grade for a smooth surface.
- Some brands shed steel wool filaments, which should not go into clay that will be recycled.
Steel wool pads are highly recommended. They remove the most amount of excess material with the least amount of effort. Small pieces of steel wool can be pulled from the pad and used for detailed work or to reach all areas of complex three-dimensional forms. Finer grades of steel wool may leave the surface quite smooth, depending upon the pressure, clay, and slip used.