PRIOR TO 2000
Ruy Lopez: Breyer System
Sicilian Defense 4: Gurgenidze
Four Knights and Belgrade Gambit
Garry Kasparov, the 20-year old Grandmaster from Baku, is already the second highest ranked player in the world and has won several top tournaments including the Soviet Championship. 52 year old Victor Korchnoi was a Grandmaster before Kasparov was even born and already had played two matches for the world title.
Kasparov vs. Korchnoi - London 1983
Sicilian ...e6 and ...d6 Systems
Sicilian - Paulsen