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by Bob Schmitz
Bob Schmitz is Assistant Professor of Ceramics at the School for American Craftsmen, Rochester Institute of Technology, Rochester, N. Y.
I think it is important to first define our terms. Wood firing means using wood as a fuel to achieve a desired temperature. Pots have, from the beginning, been fired with wood. The pots were placed in a pile on the ground, covered with wood, and the wood was burned. Most of the heat from burning the wood, however, was lost. At some time in history, a shallow hole was dug and lined with wood. Then pots were placed on the wood and a layer of broken pots were placed around and over the pieces to be fired. This was to protect the ware from sudden heat, and created a sort of crude updraft kiln. The pile was covered with more wood and burned.
In Cyprus and Crete, kilns were built much like a large barrel. The pots were loaded from the top, and broken pots were used to cover the top of the kiln. The fire box area was at the bottom of the kiln. This functioned as an updraft kiln but only fired to earthenware temperatures. The Chinese were the first to fire to stoneware temperatures, but usually protected their pots from the effects of the ash with saggers. It was the Japanese who first used the wood for more than just a source of heat. They reacted to the effect of the ash moving through the kiln and landing on the pots. They developed forms that would best use the ash glazing and flashing, the best known being the Tomba and Bizen ware. It was the study of these traditional Japanese pots that first interested me in wood firing.