chess to beat him.The old main line (6.Bg5) was an aggressive attempt by White to refute the opening and was studied intensely until the 1980s when it began to decline. Bobby Fischer, who called the Najdorf "one of the greatest creations in chess theory" favoured the Lipnitzky/Fischer attack (6.Bc4) for much of his career. He won numerous games with it as White, though in the following years counterattacking approaches were found for Black that led to its decline, though a modern variation (7...Nbd7) caused a resurgence and it appeared in the 1993 PCA World Championship match between Garry Kasparov and Nigel Short. Anatoly Karpov faced the Najdorf many times with the White pieces, and frequently opted for the Classical/Opočenský Variation (6.Be2) (inspired by Efim Geller, who acted as Karpov’s second). The Classical variation aims to castle Kingside for a more positional game, which suited Karpov's style. He contributed both to the theory and the popularity of the variation while at his peak, finding ways to exploit the weakness of the d5-square created by the Black's move 6...e5. Garry Kasparov would often transpose to the Scheveningen (6...e6) to avoid this problem when the two competed for the World Championships. In the 1980s and 1990s, a number of English players (John Nunn, Nigel Short, and Murray Chandler) began using an approach previous tried against other Sicilian variations, such as the Dragon. The English Attack, named for them, involves 6.Be3, and often leads to opposite-side castling with both sides launching a simultaneous pawn storm on opposite sides of the board. This approach has become the modern mainline and is seen regularly at the highest level. Variations Main line: 6. Bg5 Classical Main line: 6...e6 The main move. In the early days of the Najdorf 7.Qf3 was popular, but the reply 7...h6 did not allow White to obtain any advantage. Nowadays, White players almost universally respond with the move: 7.f4. White threatens 8.e5, but Black has several options: 7...Be7 8.Qf3 and now: 8...Qc7 9.0-0-0 Nbd7, this is called the old main line. At this point White usually responds with 10.g4 or 10.Bd3. After each of these moves there is a huge body of opening theory. 8...h6 9.Bh4 g5. This is known as the Argentine/Goteborg Variation. It was first played in round 14 of 1955 Goteborg Interzonal simultaneously by Argentine players Panno, Pilnik and Najdorf who were facing the Soviet grandmasters Geller, Spassky and Keres.