Paul Soldner was one of, if not the pioneer of western style Raku, introducing the combustible reduction chamber in the 1960's. Traditionally as mentioned, Raku ware was taken from the hot kiln and left out to cool, or put in water. With western style Raku, a chamber such as a trash can, would be filled with sawdust, seaweed etc, to encourage combustion. The lid of the trash can would be put on once the red hot ware was put in the can to create an intense reduction or carbonized atmosphere, turning the clay body black.
Paul Soldner HERE