There are two different styles of Raku nowadays. One is the traditional Japanese style and the other is Western Raku. The difference is Western raku takes the bowls out of the kiln and puts them in a container of leaves or newspapers or something that will burn. This is done to create very shiney and colorful glazes. It is opposite of what Rikyu wanted.
For traditional Japanese raku exist four main types of collours: black, red and white raku, and then the amber colored style called Ohiyaki. Ohiyaki is made by Ohi Chozaemon in Kanazawa city. The glaze for black raku is traditionally made from Kamogawa ishi, or stones from the Kamo river in Kyoto, and then mixed with lead. All traditional Japanese raku is made by hand because its what Rikyu thought was best.