Raku is a pottery firing technique dating back to 16th century Japan.
Modern raku pottery is loosely based on the ancient Japanese technique. When the glazed ware reaches the temperature of approximately 1800 it is removed from the kiln and is placed in a pit containing combustible materials (such as paper, pine, sawdust). The red-hot piece ignites the combustibles and the pit is then tightly covered to reduce the oxygen and stop the fire. Many interesting glaze and surface effects can be obtained using this method. Pots produced using the raku method are porous and fragile. Therefore, raku pots are generally considered nonfunctional, decorative pieces.
They do not hold water and should not be used for food or beverage.