灰釉大平鉢

Ash glaze

Ash glazes (kaiyū) are ceramic glazes made from the ashes of plants, such as wood or straw. Traditionally, these are divided into three categories: pure wood ash, which is made from the bark of trees such as oak and chestnut and has a faintly blue hue; hearth ash, which contains impurities and has a faintly bluish-green hue; and straw ash, which produces a milky-white glaze.