Players of the Grand Prix generally hate to play against an early …d5.
4. exd5
Playable, but not best. White does well to consider a speedy e5 advance, and then to avoid an early d4.
Perfectly logical are either 5. Bb5+ or 5. Nf3
Compounding his error in development by weakening his White squares, which Black immediately attacks.
It’s necessary to maintain control over f3. Perhaps 7. Be2 Qe7!? 8. Kf2 h5
or 7. Nf3 Qe7+ 8. Kf2 Nc6 9. Bg2
Also good was 8… d4 9. Nb1 Bd6 10. Nd2 Bc6 11. Bg2 but that let’s White regain control of the light squares in his camp. Now the Knight can jump into the d4 square.
Better 10. h3 although 10… Bxg2! (or 10… Nxe2 11. Nxe2 Bxg2 12. Rxg2 Bd6=/+) 11. Rxg2 Qd7 followed by castling Queenside allows Black to exploit the kingside most quickly.
10… Bxg2 11. Rxg2 Nf3+ 12. Kf2
Position after 12.Kf2
A tough move to find, and by far the best.
13. Bd2? 13. Rxh2 Ng4+ 14. Kg1 Nxh2 15. Kxh2 d4-+
13… Nfg4+ 14. Kg1 Nf3+ 15. Kh1?
White should avoid mate by 15. Kf1 d4 16. Ne4 Nxd2+ 17. Qxd2 Ne3+-+
and Black must suffer tremendous material losses to stave off mate.
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