a dedicated chess computer by Remote Control Systems, a company of former German Fidelity Electronics representative Peter Reckwitz, initially specialized in tuning of Fidelity chess computers, and since December 1985 marketing the RCS Granit single-handedly . The Fidelity Sensory Chess Challenger 9 based program by Dan and Kathe Spracklen ran on an overclocked 6502 processor at 8 Mhz. The RCS Granit played the Aegon 1986.
- Die Geschichte der Firma Fidelity - Teil 3 by Alwin Gruber, Schachcomputer.info Wiki (German)
- Remote Control Systems: RCS Granit/Granit S (German)
- Granite from Wikipedia
- Blue Mitchell - Granite & Concrete (Hadley Caliman), Blues' Blues (1972), YouTube Video