[Event "Opening Theory #15"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "Queen's Indian Defense for Black"] [Black "?"] [Result "*"] [ECO "E18"] [Annotator "KS"] [PlyCount "28"] [SourceVersionDate "2022.12.07"] 1. d4 Nf6 2. c4 e6 3. Nf3 (3. Nc3 Bb4 $1 {Nimzo}) 3... b6 4. g3 $1 {the only critical move} Bb7 {is more practical and has become trendy!} 5. Bg2 Be7 6. O-O (6. Nc3 $5 {Karpov's favorite} O-O $1 (6... Ne4 7. Bd2 {White can avoid our idea in the main line}) 7. Qc2 $5 (7. O-O {transposes to the main line}) 7... c5 $1 8. d5 $1 {s a dangerous pawn sac.} exd5 9. Nh4 (9. Ng5 Nc6 10. Nxd5 g6) (9. cxd5 Bxd5 $1 10. Nxd5 Nxd5 11. Nh4 Nb4 $1) 9... Nc6 10. cxd5 Nd4) 6... O-O 7. Nc3 (7. Re1 $5 Qc8 $5 {Yuriy Krykun} (7... Ne4 $5 8. Nfd2 d5 9. cxd5 exd5 10. Nxe4 dxe4 11. Nc3 f5 12. Bf4 Bd6 $11) 8. Nc3 Ne4) (7. d5 {AlphaZero's choice in the legendary match vs Stockfish} exd5 8. Nh4 $1 {This is the Polugaevsky gambit, which according to Kasparov, made Karpov to abandon the 4...Bb7 variation in favor of 4...Ba6 for their Wch matches Today we know that White doesn't have any advantage here} c6 9. cxd5 Nxd5 10. Nf5 Nc7 11. e4 d5 12. Nc3 (12. exd5 Nxd5 13. Nc3 Bf6 {transposes}) 12... Bf6 13. exd5 Nxd5 14. Nxd5 cxd5 15. Ne3 Nd7 16. Nxd5 Bxd5 17. Qxd5 Rc8 $11) 7... Ne4 $1 8. Bd2 $1 {And for too long, Black couldn't seriously challenge White's small edge. Until Stockfish NNUE came and showed that} (8. Qc2 Nxc3 9. Qxc3 c5 10. Rd1 d6 {[%CAl Ge7f6] has proved to be extremely solid in practice. Karpov's games in the 80s prove that}) 8... d5 $1 {A move that was always considered suboptimal in the QID but is fully playable} (8... Nxc3 9. Bxc3 Be4 $2 10. Bh3 $1 {[%CAl Gf3d2]}) 9. cxd5 (9. Qc2 Nxd2 10. Nxd2 c6 $11) 9... exd5 10. Rc1 Nxc3 11. Rxc3 Nd7 12. Bf4 c5 {Black might end up with hanging pawns, which can prove to be weak} 13. Qc2 Re8 14. Rd1 Bf6 {[%CAl Ga7a5] Black has excellent pieces and a key move is ...a5! which makes any b2-b3 ideas less good!} *