Haiyu Slipware technique

Haiyu Slipware is a technique rarely used in the otherwise commonly shared world of ceramics. Even John Mathieson, in his compilation on slipware techniques* fails to mention Haiyu Slipware, which is probably exclusively used in Japan, and only by a handful of potters.
            Haiyu Slipware, as described by my master Shibata Masaaki, in his book 'Haiyu Ash Glaze Slipware - Collected works by Shibata Masaaki, is a technique in which a wet slab of clay is first covered by an iron slip called Tatara. Next a design is trailed wet in wet with a white or different colored slip. Once the slip decoration has dried a little, the slab is laid face down over a plaster mold-usually convex to give it a shape. The slab has to be pressed down so that the trailed design becomes flattened onto the surface. The piece is then glazed with an ash glaze. This glaze simply contains at least 30 percent of ash.  The final color of the glaze varies with the different characteristic of the plants. So the ash from one tree gives a different color variation from the ash of another. The hand built pot is then fired in a wood fired kiln at 1300 degrees C.
Haiyu Slipware
            After a six month course with Shibata sensei, I returned to Auroville, in Tamil Nadu, and adapted his technique to the ash from the trees that grow around my pottery studio. Auroville is one of the world's largest reforestation projects and I use ash from the forest around me.
            Haiyu tends to become a life style, because you need to find forests and gather ash from branches and leaves that are left after clearing for timber, or after a storm. You need the time to wash and purify this ash, before you even know if it will give you anything remarkable at all, and then you have to look for a translucent glaze that will allow the slip decoration to clearly show through it. These glazes can give you the most incredible rich colors ranging from a light golden ochre, through deep iron red, puddles of green to a pale blue. Purifying the ash and removing all alkaline elements is a long and arduous process in which only the finest particles are collected through several straining with water. No coloring stains or oxides are used, other than iron oxide in the underlying slip.
            Some of the glazes break into a matt on the iron slip and stay glossy over the white slip. There is no other single glaze that I know of, that so simply produces such a variety on a single piece. Often the white slip lines are outlined by a clear dark line, which give them the impression of having been drawn with a fine pencil.
            I have now had the privilege of working with this technique for the last six years, and am constantly amazed at the beauty of the surfaces that come out of the kiln. As I have been working with this technique, I have come to realize that I only do one third of the job. Nature, in an amazing flux of high temperature chemistry does the second third-She gives me outlines, rich colors and irresistible surfaces. But the third work on the piece-especially if it is functional comes with usage. The owner of the piece, by serving food in it, washing it, rubbing it, etc. over the years adds to the richness of the glaze. This is the most beautiful part of this technique for me-the glaze interacts and goes on interacting with it's environment. The piece is never finished, but constantly by tiny stages changes and grows in beauty.The simple explanation for this are the tiny crackles that occur generally in ash glazes, and probably the fact that a matt surface receives moisture, oils etc.
Haiyu Slipware
            Haiyu Slipware has become a way of life, out here, in the tropical evergreen forest of coastal Tamil Nadu. Ready made clay is not easily available as the Indian soil is rich in iron. Glazes are made from scratch, and a wood kiln needs constant attention for a duration of up to 18 hours. I try to make the best of the lessons I understood during my time with the Shibata family. It roughly translates into the following: put energy and love into everything you do, no matter how menial the chore-do it like you were making your most precious creative piece. All of that energy, the way you lead your life-shows in your work. There are no short cuts. It's as simple as that.

John Mathieson's book 'Techniques Using Slips' is a comprehensive presentation of all sorts of Slip work by potters around the world. It is beautifully presented and written. Publishers are A & C Black London.

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