Chess Opening Theory/1. e4/1...c5/2. Nf3/2...Nc6/3. d4/3...cxd4/4. Nxd4

Open Sicilian with ...Nc6 B32 Sicilian defence → 2...Nc6 → 3...cxd4 4. Nxd4 White recaptures the pawn. They have open lines for their pieces to develop. Black has the positional advantage of two centre pawns to White's one. The two knights are at a standoff. Neither wants to take first: if Black trades knights, 4...Nxd4!?, after 5. Qxd4 White will have better control of the centre and Black cannot easily chase away the white queen. If White elects to trade, say 4...Nf6 5. Nxc6!? bxc6, Black has brought in another pawn to help control the centre and support playing d5. The main moves here are 4...Nf6, 4...e5, and 4...g6. 4...Nf6 is the main line. This develops a piece while attack the undefended e4-pawn. This elicits White to defend it with 5. Nc3 which prevents White from playing c4 and clamping down on the d5 square, where the major lines are either 5...d6, the classical Sicilian, or 5...e5, the Sveshnikov or Lasker-Pelikan variation, both of which prevent White from trading knights and playing e5 with tempo. A sideline is 5. f3, to retain the option of c4. 4...e5 immediately is the Löwenthal variation. The main line is 5. Nb5, threatening Nd6+, where 5...d6 is the Kalashnikov variation. 4...g6 is the accelerated dragon variation. This prepares to fianchetto the king's bishop, playing a dragon variation-style set-up without spending a move on ...d6 yet. The most critical approach is 5. c4, the Maróczy bind. Other moves 4...d5 is the Nimzo-American variation. 5. exd5 Qxd5 6. Be3 is most critical; 5. Bb5 is common and leads to a queenless middle game, e.g. 5. Bb5 dxe4 6. Nxc6 Qxd1+ 7. Kxd1. 4...Qb6 is the Godiva variation. This attacks White's knight and 5. Be3? to defend it drops the b2 pawn. 5. Nb3 is called for. Transpositions 4...e6 is a transposition into the Taimanov variation. It is more common nowadays to play the Taimanov with 2...e6 and 4...Nc6 instead, as the move order with 2...Nc6 allows the possibility of the sideline 3. Bb5, the Rossolimo. 4...Qc7 is the Flohr variation, which usually transposes to the Bastrikov line in the Taimanov after 5. Nc3 e6. Theory table 1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 4 5 6 7 Main Line ...Nf6 Nc3d6 Bg5e6 Qd2Be7 += Taimanov Variation ...e6 Nc3Nf6 Ndb5Bb4 a3Bxc3+ += Kalashnikov Variation ...e5 Nb5d6 N1c3Nf6 Bg5a6 += Accelerated Dragon ...g6 c4Nf6 Nc3d6 Be3Ng4 += Nimzovich Variation ...d5 exd5Qxd5 Be3e6 Nc3Bb4 += Flohr Variation ...Qc7 Nc3e6 f4 += Godiva Variation ...Qb6 Nb3Qb4+ Nc3Nf6 Bd3Ne5 a3Qb6 Be3Qd8 Be2d6 f4Neg4 Bd4e5 fxe5dxe5 Bb5+Bd7 Bxd7+Qxd7 Bc50-0-0 += ...a5 Nc3e5 Ndb5d6 Be3Nf6 Be2Be7 0-00-0 f4b6 Qd2+= Sicilian Defence References