Chess Opening Theory/1. e4/1...c5/2. Nf3/2...d6/3. d4/3...cxd4

Open Sicilian with ...d6 B53-B56 Sicilian defence → 2...d6 → 3. d4 3...cxd4 With 3...cxd4, Black breaks up White's two-pawn centre and achieves a majority of central pawns and a semi-open c-file, expecting the pawn to be recaptured on the next turn. 4. Nxd4 is the main move, centralising the knight, which eyes key squares such as b5 and f5. This was one of the main purposes of 2. Nf3, allowing White to recapture this d4-pawn with the knight rather than the queen, thus saving valuable tempi. 4. Qxd4 is a minor sideline, known as the Chekhover Sicilian. This is less common as Black can play 4...Nc6 to chase away the queen. In order to avoid losing tempi, White usually must give away the bishop pair with 5. Bb5, and after 5...Bd7 6. Bxc6 Bxc6 Black gains the advantage of the two bishops. Nevertheless, this line is playable and could be used as a surprise weapon if Black is only prepared for the lines after 4. Nxd4. Instead of recapturing the pawn, 4. c3, the Tartakower gambit, looks to gambit it for development. This is like a delayed Smith-Morra gambit, but because Black has already committed a pawn to ...d6, if they accept the gambit certain common defences are closed off to them. Commonly Black declines with 4...Nf6. Theory table Main line 4. Nxd4 Nf6 5. Nc3 e6 + Chekhover Sicilian 4. Qxd4 Nf6 5. e5 Nc6 6. Bb5 Qa5+ Tartakower gambit 4. c3 dxc3 5. Nxc3 Nf6 References See also Sicilian Defence fi:Shakkiaapinen/Peli/1. e4/1...c5/2. Rf3/2...d6/3. d4/3...cxd4