The following one looked so strange at first that I thought I had a bug:
[D]4r1k1/ppq1rppp/2pb2n1/3p2Pn/3P4/1P1BP2P/P1P1N3/R1B2RQK b - -
Glaurung (black) surprised me by playing 23... Re4!? This was almost certainly played as a positional sacrifice. The game was played at a time control of two minutes per game, with one second increment, on a single core of a 2.8 GHz Core Duo CPU. I doubt that Glaurung would see any very deep tactics at such a fast time control.
Do any other engines like Re4 here? Is it really a strong move? If it is, is it possible to explain the point of the sacrifice in terms an average human player can understand, without giving a ton of variations?
If I recall correctly, Glaurung's score at this stage of the game was about +1.5. Glaurung went on to win quite quickly and convincingly, but perhaps because of mistakes by the opponent. The full game:
Code: Select all
[Event "Computer chess game"]
[Site "cm-84.215.94.43.getinternet.no"]
[Date "2008.05.02"]
[Round "2"]
[White "Toga II 1.4.1SE"]
[Black "Glaurung 080502"]
[Result "0-1"]
[TimeControl "120+1"]
1. f4 d5 2. Nf3 Nf6 3. b3 Bg4 4. e3 e6 5. Bb5+ Nbd7 6. O-O c6 7. Be2 Rc8 8.
Bb2 Be7 9. h3 Bxf3 10. Bxf3 O-O 11. Nc3 Re8 12. Qe1 e5 13. fxe5 Nxe5 14.
Be2 Bd6 15. Qf2 Qc7 16. Kh1 Ng6 17. g4 Be5 18. d4 Bg3 19. Qg1 Bd6 20. Bd3
Re7 21. g5 Nh5 22. Ne2 Rce8 23. Bc1 Re4 24. Bxe4 Rxe4 25. Qf2 Qd7 26. Qf5
Qe8 27. Qf2 Nh4 28. Kg1 Qe7 29. Bd2 Qxg5+ 30. Kh1 Qg6 31. Rg1 Qe6 32. Qf1
Nf5 33. Qf3 Nfg3+ 34. Kg2 Rh4 35. Nxg3 Nxg3 36. Raf1 Qxh3+ 37. Kf2 Ne4+ 38.
Ke1 Qxf3 39. Rxf3 Rh2 40. Ba5 b6 41. Bc3 Rxc2 42. Kd1 Rxc3 43. Rg2 h5 44.
Rh3 Bf4 45. Re2 g5 46. Rf3 Kg7 47. Rh3 g4 48. Rxh5
{White resigns} 0-1