Ottomatic Slim

John Len Chatman (September 3, 1915 – February 24, 1988), known professionally as Memphis Slim, was an American blues pianist, singer, and composer. He led a series of bands that, reflecting the popular appeal of jump blues, included saxophones, bass, drums, and piano. A song he first cut in 1947, "Every Day I Have the Blues", has become a blues standard, recorded by many other artists. He made over 500 recordings.

He was posthumously inducted into the Blues Hall of Fame in 1989.