Pianist. Dutch self-taught pianist who's made himself one of Europe's best session players. De Graaff led a trio from 1959 to 1962, then joined The Jazzopters for a year. He then headed his own quartet until 1964, at the same time playing with Erwin Some and Gijs Hendriks. De Graaff formed a new group in 1964 that stayed together until the '80s. He also played with a number of visiting American musicians, among them Hank Mobley, Lee Morgan, Johnny Griffin, Art Taylor, Clifford Jordan, Cecil Payne, Dexter Gordon, Clark Terry, Sonny Stitt, Philly Joe Jones and Arnett Cobb. He made several appearances in New York, and was awarded the Dutch National Jazz Prize in 1980.