Gyubera are Japanese wooden throwing ribs that have been traditionally used to create large platters and deep bowls (1, 2) in places such as Arita and Karatsu, which are pottery production regions in Kyushu (the third largest island in southern Japan). When discussing how to use gyubera forming ribs, it’s useful to contrast them with the other kinds of Japanese throwing ribs.
Using Points, Lines, and Plane Surfaces
You can divide Japanese throwing ribs into three groups based on how they form the clay: the first group uses points on the tool; the second group uses the edge profile or shape; and the third uses the plane surface of the tool. Kimegote (see PMI November/December 2014) and nobashigote (see PMI May/June 2015) are both designed so that the potter uses the edge profile of the tools to shape the clay. Kimegotes are molding ribs; their curved shapes form the interior profiles of pots, and they are useful for throwing multiples. Nobashigotes are stretching ribs, which function similar to your inside hand when throwing, and they stretch and smooth the clay surface on the inside of the forms.
Kimegote and nobashigote appear similar: when using kimegote, the inside hand is fixed in place and the outside hand helps to support the clay as it conforms to the curve of the rib; the nobashigote rib is used as a substitute for your inside throwing hand, and moves with your outside hand as it shapes the pot.
2 Gyubera, also called cow’s tongue ribs, are shaped like the letter J, are slightly curved, and come in different lengths and widths.
3 Open up the bottom just enough to fit the tool. Always keep the rib wet when applying it to the clay surface.
4 Sandwich the rib between your fingers/ palm on the front and your thumb on the back of the tool as you pull the clay out.
Egotes (see PMI November/December 2015) are throwing sticks that are used to shape the interior of narrow-necked forms. Substituting for your inside throwing fingers, the egote is pressed against the interior wall of the form in points, moving from the bottom to the neck of the form.
Gyubera ribs use the full width of the plane surface of the tool. Gyubera literally translates to “cow’s tongue,” a name it gets from the contour of the tool. It’s shaped like the letter J, has a slightly curved surface, comes in different lengths and widths (see 1, 2), and is often used for throwing bowls. The curved surface toward the tool’s tip is applied to form the interior, substituting for your inside throwing hand, with the angles applied determining the form’s profile.
Throwing a Bowl: Nobashigote vs. Gyubera
A gyubera’s function is similar to a nobashigote in the way that both ribs substitute for the inside throwing hand and form the interior of a bowl. The following explains the differences in usage.
With nobashigote, the edge profile of the tool touches the clay, and the rib stretches clay in one direction only, from the center to the rim, so you have to throw the preliminary form first before applying the rib. Think of a nobashigote as a finishing rib.
5 When pulling, support the tool with the thumb of your outer hand while your fingers trace and support the form’s exterior.
6 Apply the flat side of the rib and move from the bottom to the rim to create a plane surface.
7 A gyubera is not a common tool, but if you can master its usage, you will be able to create a very clean interior.
When using gyubera, the potter employs the plane surface, and the tool can be pushed down into the clay to change the depth of the form as well as stretch and pull the clay to form the bowl’s profile. It’s both a forming and a finishing tool.
With a gyubera, once you center a ball of clay and make a hole to create the bottom and open up the form just enough to allow the rib to enter the form (3), you can do the rest using the tool, pulling the clay out (4), compressing the bottom, stretching and pulling up the clay walls (5, 6), all while using the rib.
While a gyubera is not a common tool, if you can master the usage, you will be able to create a very clean interior (7), and also create larger forms that are difficult to throw with your hands alone.
Naomi Tsukamoto and her husband recently opened a new flower shop with a clay studio attached to it in Japan. Since then, she has been exploring the many ways that flowers and ceramics can collaborate.