Chess Opening Theory/1. e4/1...c5/2. Nf3/2...Nc6/3. d4/3...cxd4/4. Nxd4/4...g6/5. Nc3/5...Bg7/6. Be3/6...Nf6/7. Bc4/7...O-O

Modern Bc4 variation B35 Sicilian defence → Accelerated dragon → Modern Bc4 variation 7...O-O Black castles. White would like to continue their plan to long castle and assault Black's king side, but again they must take additional time to prepare it. Otherwise... 8. Qd2? to make way for long castling is answered with 8...Ng4!. This uncovers an attack on the knight on d4 while also attacking White's dark square bishop, which is a valuable piece needed to contest Black's bishop's control of the dark squares. To save the bishop, White is compelled to initiate the trade of knights themselves, 9. Nxc6 dxc6 10. Qxd8 (10. O-O-O?! Qxd2 11. Rxd2 Nxe3 loses the bishop pair anyway; 11. Bxd2?? hangs 11...Nxf2 with a fork) 10...Rxd8 11. Bg5 + and Black stands better. White may try 8. f3?! to prevent ...Ng4, so that they can then play Qd2 and O-O-O. However, 8. f3 is answered with 8...Qb6!. This move attacks b2, so if e.g. 9. O-O? Qxb2! 10. Ncb5 Qb4 11. Be2 Nxd4 12. Nxd4 ++ and Black escapes with a clean pawn. However the greater danger of 8...Qb6! is that it brings a second attacker to d4, and Black is ready to uncork a third. If 9. Qd2?? Nxe4! attacks the queen, while discovering an attack on d4 (10. fxe4 Bxd4 11. Bxd4 Qxd4 12. Qxd4 Nxd4 ++). 9. Bb5? is imaginative, but again falls afoul of 9...Nxe4! (10. fxe4 Bxd4 11. Bxd4 Qxd4 12. Qxd4 Nxd4 ++). The best try is 9. Bb3: 9...Nxe4 still follows, but White can at least recover the material with 10. Nd5 Qa5+ 11. c3 Nf6 12. Nxc6 dxc6 13. Nxe7+ -. Therefore White must begin with 8. Bb3. This places the bishop on a safer square where it is guarded, and where it prevents ...Qb6 from exerting any pressure on the b2 pawn. White can then follow with f3 to prevent ...Ng4, Qd2, and O-O-O. 8. O-O is a less challenging variation for Black to face. Black may respond 8...d6 to transpose into a good version of the regular dragon variation, or 8...Nxe4!, a temporary piece sacrifice where after 9. Nxe4 d5 10. Nxc6 bxc6 11. Bd3 dxe4 12. Bxe4, the game is equal. Theory table References See also