TCEC Season 17 Division P Game 58: Ethereal-Houdini
|Game||Season 17, Division Premier, Game 58|
|Links|| TCEC archive|
|Position after 15. Kf2|
1. d4 g6 2. e4 Bg7 3. c4 d6 4. Nc3 Nf6 5. Bd3 O-O 6. Nge2 Nc6 7. O-O Nh5 8. Bc2 e5
End of book. The book exit is into King's Indian Defense, normal variation. The move order is unusual transposing from Modern Defense, Averbakh system on move 4... Nf6.
9. d5 Nb4
Mainline book move was 9... Ne7.
10. Ba4 f5 11. a3 Na6 12. b4(N)
Pushing the b-pawn on the queenside is logical for some counterplay against black's ideas on the kingside. In the game, white allowed black to freely push the f4-pawn. If that was not desired, then 12. Ng3 could have also been played. For example: 12. Ng3 Nxg3 13. fxg3. To open up the f-file here with fxg3, black would have to allow white exchanging a pair of rooks, which would soften the attack. In this line, black was also discouraged to push the f-pawn immediately with 12... f4?!, since while 13. Nxh5 gxh5 would open the g-file for black, it would also make white's defense easier.
12... f4 13. f3 g5 14. h3
White needed to slow down black's g-pawn push. Now black will have to play h5 before g4.
14... Nf6 15. Kf2 (diagram)
The king walk begins. Under the looming black pawn storm to attack the kingside, the white king begins its journey to the safer side of the board. However, this takes multiple tempi, which white could have arguably spent for more active pursuits.
The king journey was not enforced by any means, as white also had the option to close the kingside. For example: 15. Qd3 h5 16. Ra2. In this variation, opening the position would be a mistake for black: 16... g4?? 17. g3 gxf3 18. Rxf3 Bxh3 19. gxf4
Bg4 20. Rf2 and it would be white attacking on the kingside. So, black would have to allow white make some room with 16... Nh7 17. g4, and then choose from allowing the kingside to be closed with a move such as 17... Rf6, or keep it open but allow white to get into contention with 17... fxg3 18. Nxg3 Bxh3.
|Position after 28. Rad1|
15... Nb8 16. Bb2 a5 17. Ke1 Bd7 18. b5
Pushing the b-pawn here might have been a small inaccuracy, as it makes white's light-square bishop significantly worse than its counterpart. The b-pawn push also closes the queenside prematurely, limiting white's breaking options, and thus, allowing black to take control of the game for the time being. Perhaps more flexible would have been to exchange the bishops first with 18. Bxd7 Nbxd7 and than decide what to do on the queenside. For example, 19. Nc1 Nh5 and then 20. Nd3 to prepare for the c5 push, or 20. Nb3 to ask what black wants to do with the a5 pawn.
18... Be8 19. Bb3 Nbd7 20. Na4 h5 21. Kd2 g4 22. hxg4 hxg4 23. Nc1 Bh5
The quality difference of the light-square bishops is now getting pronounced.
White might be tempted with taking the g4 pawn by fxg4 to stop black advancing the kingside pawns. To do so, white would first have to protect the e4-pawn. However, this is easier said than done and white's bishop is tied on the a2-g8 diagonal. To illustrate: 24. Bc2? c6! 25. Ne2 cxb5 26. cxb5 Nb6 27. Nxb6 gxf3 28. gxf3 Qxb6 and the black queen is dangerously entering white's territory. However, while the bishop is on b3, black's c6 break has less punch, because white can simply take it: 24. Qe2 c6 25. dxc6 bxc6 26. bxc6 Nb8 27. c5+. The fact that the c-pawn push here is with a check makes all the difference.
24. Qe2 Bg6 25. Nd3 Nh5 26. Rfe1
White has to evade the fork of Ng3.
26... Ng3 27. Qf2 Qh4 28. Rad1 (diagram) b6
Black decides to put a seemingly hard stop for any white queenside breaking ideas. If left unchecked, white would have eventually played c5 (or in some cases even b6) to open up the queenside for counterplay, and further, undermining black's center and attempting to liberate the bishops that are now stuck behind the pawn wall.
|Position after 38. c5|
29. Kc2 Qh2 30. Kb1 Nf6 31. Ka2 Rae8 32. Nc3 Nh7 33. Rd2 Ng5 34. a4 Rf7 35. Bd1 Bf6
White is still in no position to resolve the kingside tension to prevent black from slowly increasing the pressure. For example, 36. fxg4?? N5xe4 37. Nxe4 Nxe4 38. Qe2 Bh4 39. Rf1 Ng3 and black would win the exchange and soon break through with moves such as e4 and f3.
36. Rc2 Rh7 37. Nb1 Kf7
This might have been the time for black to force the matter with 37... N5xe4 38. fxe4 Nxe4 and argue that the e5/f4/g4 pawns against white's g2 pawn is worth the piece sacrifice. But black didn't do so, allowing white to get back into the game with a queenside pawn break.
38. c5 (diagram)
Why does this seemingly desperate move work? The simple answer is that it creates a weakness in black's pawn formation.
White's main alternative here was to wait and allow black to finally resolve the kingside tension: 38. Nd2 gxf3 39. Bxf3 Nxf3 40. Qxf3 Bh5 41. Qf2 Bh4. But now black has the initiative, and it is likely a decisive one. Or at least, only black would play for a win.
White still could not take the g4 pawn, as 38. fxg4?? N5xe4 39. Qg1 Ng5 and black's e5/f4 pawns will be decisive.
Back to 38. c5:
- If black takes with the b-pawn, as happens in the game, then the black a5-pawn will be a permanent weakness requiring constant attention. Should the pawn fall, white would have a protected outside passed pawn.
- If black takes with the d-pawn, that would permanently weaken black's e5-pawn and white would get counterplay by playing against it. For example: 38... dxc5 39. Na3 gxf3 40. gxf3 Qxf2 41. Rxf2. Sooner or later, Nc4 is coming and perhaps d6 could be an idea.
- White's immediate threat is cxb6 to win both the b6 and a5 pawns. For example 38... Kg7?? 39. cxb6 cxb6 40. Qxb6 Nf7 (to protect d6) 31. Qxa5. Two connected outside passers will be decisive.
|Position after 57. Ng4|
38... bxc5 39. Nd2 gxf3 40. Bxf3 Rg7 41. Rc3 Re7
Somewhere here black started to play too passively, and finally began to lose the advantage. Perhaps better was to aim for something like 41... Qh8 42. Rc4 Rh7 43. Rg1 Rh2 44. Qe1 Bh5 45. Qd1 Qh7 46. Bxh5+ Qxh5 47. Qxh5+ Rxh5 48. Bc3 Ra8 49. Kb3 Ne2 50. Rf1 Nxc3 51. Rxc3 with the idea of exchanging white's dark-square bishop that can easily target at the a5-pawn.
42. Rc4 Rg8 43. Rg1 Ree8 44. Kb3 Rc8 45. Ka3 Ra8 46. Kb3 Rge8 47. Qe1
Black is playing passively, whereas white's shuffling has a purpose. The queen moves to the queen-side before the rook moves to e1. This frees up white's minor pieces from defending e4 to attacking a5.
47... Rh8 48. Qd1 Rh7 49. Re1 Qh6 50. Nf2 Qg7 51. Rc2 Kg8 52. Nc4 Qf8 53. Bc3 Ra7 54. Rb2 Qa8 55. Ka3
The black heavy pieces are now tied in protecting the a5 pawn while white is adding pressure to it with the light pieces. White's two previous moves add protection two the a4-pawn to prepare for capturing the a5-pawn, and the rook on the b-file is also supporting a potential b-pawn push.
55... Be7 56. Qb1 Bf8 57. Ng4 (diagram)
Finally, white is able to play on the kingside. The immediate threat is now Nf6+ forking.
57... Rg7 58. Qc2
Here white had a more decisive path to victory: 58. Nh6+ Kh8 59. Nf5. The immediate threat by white is to push b6. For example: 59... Rf7 60. b6 Rb7 61. bxc7 Rfxc7 62. Nfxd6 and white is breaking through decisively. After 59. Nf5 black has many options to choose from, but none seem to work.
But as white procrastinated by a move, black brings the queen to stop the immediate tactics and gives up the a5-pawn in the process. A non-forcing series of exchanges ensues in a position where white has two minor pieces for a rook and a pawn.
|Position after 72. Rb3|
58... Qd8 59. Nxa5 N5xe4 60. Rxe4 Bxe4 61. Bxe4 Nxe4 62. Nh6+ Kh8 63. Qxe4 Rxa5
After the exchanges, white is still threatening Nc6 to fork the queen and the rook. Black is not really in a position to prevent giving up the exchange, as it would end up in a losing endgame after some brilliant tactics. So, black simply gives the exchange back, thus saving some pawns. White still has the protected outside passer.
An example line of trying to keep the exchange: 63... Ra8 64. Nf5 Rf7 65. Nc6 Qg5 66. Nxe5 dxe5 67. Qxe5+ Bg7 68. Nxg7 Qxe5 69. Bxe5 Rxg7 70. Bxg7+ Kxg7 71. d6. The endgame is easily winning for white, as the black rook cannot stop both the a/b pawns alone.
White wants the kingside rook instead.
64... Ra8 65. Nxg7 Bxg7 66. a5 Kg8 67. a6 Qe7 68. Rb1 Qf7 69. Ba5 Kf8 70. Kb3 Kg8 71. Kc4 Rb8 72. Rb3 (diagram) f3
Now white is completely winning, and black plays a move of desperation, postponing the inevitable. The threat was 72... Ra8 73. Rh3 Qe7 74. Qh7+ Kf8 75. Rh5 Bf6 76. Qf5 Kg8 77. Bxc7 creating the connected passers on the a/b files.
|Position after 89... Kg6|
73. gxf3 Rf8 74. Qg4 Qf4+ 75. Qxf4 Rxf4+ 76. Kc3 Ra4 77. Bxc7 e4+ 78. Kd2 c4 79. Rb1 Bd4 80. fxe4 Ra2+ 81. Ke1 c3 82. Bxd6 Kf7 83. Rb3 Rb2
One final trick. If 84. Rxb2?? now, then cxb2 and black is the first to queen.
84. a7 Bxa7 85. Rxc3 Bf2+ 86. Kf1 Bh4 87. Rc7+ Kg8 88. Rc8+ Kf7 89. e5 Kg6 1-0. (diagram)
White wins by TCEC win rule.
Example continuation: 89... Kg6 90. Rc4 Rb1+ 91. Kg2 Bd8 92. Rb4 Rd1 93. b6 Bxb6 94. Rxb6 Rxd5 95. e6 Rg5+ 96. Kf3 Rf5+ 97. Ke4 Rf1 98. e7 Re1+ 99. Kd5 Kf5 100. Rb4 Rd1+ 101. Rd4 Re1 102. Rf4+ Kg5 103. Re4 Rd1+ 104. Ke5 Rf1 105. e8=Q Rf5+ 106. Kd4 Rf1 107. Be7+ Kh6 108. Rh4+ Kg7 109. Rg4+ Kh7 110. Qh5#.