Another Gruenfeld

1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 Bg7 7. Bc4 c5 8. Ne2 O-O 9. O-O Nc6 10. Be3 cxd4 11. cxd4 Na5 12. Bd3 Bg4 13. f3 Be6 14. d5 Bxa1 15. Qxa1 f6 16. Bh6 Re8 17. Kh1 Rc8 18. Nf4 Bd7 19. e5 Nc4 20. e6 Bb5

The usual move here is 20...Ba5, played 40 times in the 365chess database to 12 for 20...Bb5. However, black's 20...Bb5 actually scores slightly better for black than the more usual move (46% to 41%).

21 Nxg6

I played this move, which is the normal response to 20...Ba5. However, this was played in only one of the 12 games with 20...Bb5, with 21 Qe1 played in the other 11 games. After 21 Qe1, the most usual continuation is 21...Nd6 22. Bxg6 hxg6 23. Qg3 Bd3 24. Nxd3 Kh7 25. Nf4 Rg8 26. Qh3 Rh8 27. Bf8 Kg8 28. Bxe7 Qxe7 29. Qxh8 Kxh8 30. Nxg6 Kg7 31. Nxe7 Rc7 32. g4 Rxe7, after which 33 Rc1 drew, but 33 Kg2 lost.

21...hxg6 22 Bxg6 Ne5 23 Be4 Bxf1?

In the only game in the database, black played 23...Qa5, preventing white's Qe1 move, and drew.

24 Qxf1? (21 Qe1) 24...Qa5 (Rc4) 25 Qf2 Kh8??

This is the losing move. Stockfish gives 25...Ng4, giving back material to blunt white's attack.

26 Qh4 Nxf3 27 Bg2+! Black resigns 1-0