Ashes obtained from burning wood from miscellaneous trees in the hearth. The main ingredient is lime carbonate, which is mixed with potassium carbonate, soda carbonate, aluminum oxide, phosphoric acid, iron oxide, and magnesium oxide. The potassium carbonate and soda carbonate are removed by washing in water, and the mixture is used as a fluxing agent for glazes for many years. This glaze is called an ash glaze, and usually shows a yellowish brown color when oxidized, and a light blue-green or brownish-green color when reduced.
