Raku is usually made of an open body containing particles of already fired clay. It originated in Japan around the 16th century and its original makers (the Raku family) intended it for use in tea ceremonies. Types of Raku include Kuro (black) raku, made with a thick, brown-tinged iron or lead glaze; aka (red) raku, made with a transparent glaze on an orange body; and white raku, thickly coated with white glaze.

Raku requires a unique glaze and firing process. The glaze usually contains a higher amount of copper than many other glazes. The pieces are fired at 1800F degrees, removed, and placed in an uncovered metal can (usually a barrel or trash can) filled with paper or thin wood chips. As the heat from the piece ignites the wood or paper, the copper in the glaze reacts with the paper. Resulting from this remarkable metamorphosis is an explosion of color on the surface of the glaze. After the can is covered with a lid and the piece cools for at least an hour or until cool enough to handle, the finished ware flourishes a glaze with a detailed map of colored cracks and patterns.

Sources:
Zug, Charles III. Turners and Burners: The Folk Potters of North Carolina. Chapel Hill: UNC Press, 1986.
Cameron, Elisabeth. Encyclopedia of Pottery & Porcelain: 1800-1960. New York: Cameron Books, 1986

Moravian - Raku