TCEC Season 16 Division P Game 109 – ScorpioNN-AllieStein
|Game||Season 16, Division P, Game 109|
|Links|| TCEC archive|
|Position after 23... R6e7|
1. e4 e5 2. Nf3 Nc6 3. Bb5 g6 4. O-O Bg7 5. c3 a6 6. Ba4 d6 7. d4 Bd7 8. Re1 Nge7
End of the book moves.
9. dxe5 Nxe5 10. Nxe5 Bxe5 11. Bb3 Nc6 12. Nd2 O-O
Novelty in the Lichess masters database.
13. Nf3 Bf6 14. Bh6 Re8 15. Qd2 Be6 16. h3 Bxb3 17. axb3 Bg7 18. Rad1 Re6 19. Re2 Qd7 20. Bxg7 Kxg7 21. Rf1 Rae8 22. Rfe1 h6 23. Re3 R6e7 (diagram)
Black is starting to build up tension towards the pawn on e4, claiming some initiative from white. Black has the option to play d5 later to add pressure on the e-file.
|Position after 33... Qb5|
24. b4 Ne5 25. Nxe5 Rxe5 26. Qd4 Kg8 27. f3 Qe7
White could have played 28. f4 here to prevent black's d-pawn push.
28. R3e2 d5 29. Kf1 Qg5 30. Qa7 dxe4 31. Qxb7 exf3 32. Qxf3 Rxe2 33. Rxe2 Qb5 (diagram)
After simplifications, black has managed maintain to keep tension in the position and is now pinning the rook on e2. White king side-steps the pin, but does it in the wrong direction. The problem with the move played (34. Ke1) is that after the exchanges (34... Qxe2 35. Qxe2) black has the option to play 35... Kf8 rather than 35... Rxe2. This brings the black king faster to the center, denying white the required counterplay to draw the game. Based on the engine evaluations during the game, it seems that white either missed the move 35... Kf8 or misevaluated the resulting king-pawn endgame as a draw.
Move 34. Kf2 would have also side-stepped the pin without allowing white to play 35... Kf8. This would have likely been a draw. See the discussion below on variation 35... Rxe2+.
34. Ke1 Qxe2+ 35. Qxe2 Kf8
To exemplify the importance of winning the tempo with Kf8, variation 35... Rxe2+ 36. Kxe2 Kf8 37. Kd3 Ke7 38. Kc4 Kd6 39. b5 axb5+ 40. Kxb5 would likely have been a relatively straightforward draw for the engines. In this variation, white would have managed to gain a pawn break option on the queenside to balance black's pawn break option on the kingside.
|Position after 41... Kf6|
36. Qxe8+ Kxe8 37. Ke2 Kd7 38. Kd3 f5 39. Ke3 Kd6 40. Kf4 Ke6 41. h4 Kf6 (diagram)
Now the rationale why the king-pawn endgame favors black becomes clear. The queenside black pawns blockade the white pawns. White pawns cannot break without the support by the white king. But on the kingside, the black pawns can break unsupported. This imbalance gives more freedom for black, and ultimately wins the game.
The white king is now forced to retreat and the rest is a formality. Would white have been stubborn, g5 was coming regardless sooner or later. For example: 42. g3 g5+ 43. hxg5+ hxg5+ 44. Ke3 Ke5.
42. Ke3 Ke5 43. g3 g5 44. Kf3 f4 45. gxf4+ gxf4 46. Ke2 Ke4 47. h5 Kf5 48. Kf3 Kg5 49. c4 Kf5
Now as soon as the white king moves, black king gets to escort the f-pawn for queening.
50. c5 Kg5 51. Ke4 Kg4 52. b5 axb5 53. Kd5 f3 54. Kc6 f2 55. Kb7 f1=Q 56. Kxc7 Qb1 57. Kd6 Kxh5 58. Kd7 Qxb2 0-1
The game was adjudicated as black win based on the Syzygy 6-men endgame tablebase.