Raku

Rakuyaki (樂焼) or Raku (樂) is a form of pottery characterized by low firing temperatures (resulting in a fairly porous clay body), lead glazes, and the removal of pieces from the kiln while still glowing hot. The form was created in Japan, and is the traditional pottery form for creating bowls for the Japanese tea ceremony.

Typically pieces removed from the hot kiln are placed in masses of combustible material (e.g., straw, sawdust, or newspaper) in order to provide a reducing atmosphere[?] for the glaze, and to color the exposed clay surface with carbon. Often glazes which craze (present a cracked appearance) are used, and the crazing lines take on a dark color from the carbon as well.