Sicilian Defence, Chekhover Variation Sicilian Defence, Chekhover Variation The Sicilian Defence, Chekhover Variation (also sometimes called the Szily Variation or Hungarian Variation) is a chess opening named after Vitaly Chekhover, from the game Chekhover–Lisitsin, Leningrad 1938. It is defined by the moves: On move four White ignores the standard opening principle to not develop the queen too early in the game. Although the Chekhover Variation is somewhat rare at grandmaster level, it is not uncommon among amateurs. The "Encyclopaedia of Chess Openings" (ECO) assigns code B53 to this opening. Black's main response to the Chekhover Variation is 4... Nc6 immediately attacking White's queen, leading
Ruy Lopez (also called the Flohr–Zaitsev Variation) was advocated by Igor Zaitsev, who was one of Karpov's trainers for many years. A Karpov favourite, the Zaitsev remains one of the most important variations of the Ruy Lopez. With 9...Bb7 Black prepares to put more pressure on e4 after 10.d4 Re8 11.Nbd2 Bf8 when play can become very sharp and tactical. One drawback of this line is that White can force Black to choose a different defence or allow a draw by repetition of position with 11.Ng5 Rf8 12.Nf3. Karpov tried 9...Nd7 several times in the 1990 World Championship match, but Kasparov achieved