Kuro-rakku is a type of raku ware with a black opaque glaze. Since kuro-rakku is fired with a high flame, it is fired over charcoal in a small nishiki-gama, which has a different structure from that of ordinary nishiki-gama, with a flagon attached. The hot, red pieces are removed from the kiln with scissors and immediately soaked in hot water as is the usual practice in Kuro-ragaku. The pieces that are not soaked in hot water are extremely hard and make a hard sound when struck. To get the soft and shiny feeling of kuro-ragaku, it must be soaked in hot water. (The Secret of Raku Ware)
