"Raku" is a 16th century Japanese firing technique in which the clay pieces are heated up to a temperature of about 1685 degrees F., and then removed with tongs to a post firing reduction chamber. the chamber is filled with combustible materials like sawdust or straw, paper, leaves, etc., which ,of course catches on fire when the hot pots are put in.The glazes, which are saturated with copper, cool in an atmosphere that is what we call "reduced" of oxygen because the fire surrounding the pottery is pulling oxygen out of the copper in the glaze and the glaze can't oxidize and go green like a copper penny does over time. the glazes turn red with flashes of blue, magenta, and yellow. Where the clay is left bare, the smoke from the covered reduction chamber impregnates itself into the clay and turns it black, while many glazes crack under the thermal shock of being removed from a white hot kiln into whatever the ambient temperature happens to be and the smoke gets into those crack giving Raku a characteristic ancient look. There is a point where the fire takes control and nature has it's way with each piece. This is why the history of the process is so intriguing.

Raku is one of my favorite methods of showing students how cool clay is. I love showing students what happens in the kiln as their pieces are fired. They can actually see the glazes bubble and smooth over and watch as their pieces are removed from the kiln to the reduction chamber.