TCEC Season 17 CPU League 1 Game 380: Nemorino-Andscacs
|Game||Season 17, CPU League 1, Game 380|
|Links|| TCEC archive|
|Position after 8... Nbd7|
1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. f3 O-O 6. Be3 e5 7. Nge2 c6 8. Qb3 Nbd7 (diagram)
Book exit into King's Indian Defense, Saemisch Variation. Lichess masters database has 22 games for this position with heavy preference for white. The sole database move here is 9. O-O-O, which is logical for increasing the pressure on the d-file.
|Position after 16. Nf5|
9. O-O-O exd4
Black relieves a bit of center pressure and opens up avenues for the fianchettoed bishop on g7. The exd4 by black is a typical plan, although the masters usually play the move a bit later.
10. Nxd4 Qc7(N) 11. g4 a6 12. h4 b5
After opposite-side castling, the game is often a race of first to attack decisively. But perhaps this is now getting a bit double-edged for black. More solid approach would have been to slow down white's plans first. For example: 12... h5 13. gxh5 Nxh5 14. Rg1 and there are no open files on the kingside.
13. h5 Ne5
Black had no good way to stop white of opening the kingside a bit. But as black was kind of committed to the attacking race, perhaps it would have been logical to continue it:
- 13... b4 asking white to commit to the attack and sacrifice a piece. For example:
- 14. Nce2 c5 15. hxg6 cxd4 16. gxh7+ Kh8
- 14. hxg6 bxc3 15. Qxc3 Ne5 16. gxh7+ Kh8. In both these lines black is up a piece, although white has attacking compensation.
- 13... bxc4 14. Qc2 c5 15. h6 Bh8 16. Nf5 gxf5 17. g5 Nxe4 18. fxe4 opening lines for both sides.
But 13... Ne5 also had a point in questioning the idea of Nf5 by white in many lines, as the e7 square where the knight is heading would be controlled.
14. hxg6 hxg6
The h-file is now open. Black's hand was forced, as either 14... fxg6?? 15. cxb5+ Kh8 16. bxc6 or allowing 15. gxh7+ by other moves would have been disastrous for black.
15. Be2 Bd7
Not often engines at this level play an outright losing mistake in the middle game, but 15... Bd7 was one if any. Black had multiple better alternatives such as Rd8, b4, or Re8, although it has to be said that black's position was already difficult. The problem of the bishop move is that it blocks the queen's access to the e7 square, which enables a shocking move by white:
16. Nf5 (diagram)
The simple threat is now Ne7# mate, so black has to react. Example lines:
- To exemplify the attacking threat, if black simply parries the mate: 16... Rfe8 17. Nxg7 Kxg7 18. Bh6+ Kg8 19. Bg5 Kg7 20. Bxf6+ Kxf6 21. f4. White's attack is unstoppable
- Not accepting the sacrifice to prevent opening the g-file: 16... Bxf5 17. gxf5 bxc4 18. Qc2 d5 19. f4 Neg4 20. Bxg4 Nxg4 21. e5. In this line, the black knight on g4 is tied with controlling the h2 entry square for the white queen. The threat of white doubling on the h-file along with the strong pawn center is deadly.
However, black chose to accept the sacrifice, which was perhaps the best of the bad options. But this opens both the g and h-files for the white rooks.
|Position after 23. Bg7|
16... gxf5 17. gxf5 Rfe8 18. Rdg1 d5 19. Rxg7+
Another sacrifice! The simple 19. cxd5 and multiple other moves were also winning, but opening the king some more with an exchange sacrifice was faster.
19... Kxg7 20. Bh6+ Kg8 21. Qd1
White's threat is now simple: 22. Qg1+. Giving back some material with 21... Ng6 would not help: 22. Qg1 d4 23. fxg6 dxc3 24. gxf7+ Kxf7 25. Qg7+ Ke6 26. Bg5 cxb2+ 27. Kb1 Qe5 28. Bxf6 Qxf6 29. Rh6 Qxh6 30. Qxh6+ Ke7. Even if black has two rooks for white's queen, the white connected e/f passers would run too quickly.
21... Qb6 22. Qd2
After black prevented Qg1, white news the threat of moving the queen on the g-file with Qg5.
22... Nh7 23. Bg7 (diagram)
The black knight on h7 prevented Qg5, so the white bishop makes room for the queen on h6. The bishop cannot be taken, as it would lead in a simple forced mate: 23... Kxg7 24. Qh6+ Kg8 25. Qxh7+ Kf8 26. f6 Qe3+ 27. Kb1 Qg5 28. Qh8+ Qg8 29. Qh6+ Qg7 30. Qxg7#
Now black must give back material to prevent Qh6 deciding the game quickly.
|Position after 29. Nxd5|
23... Bxf5 24. exf5 Nxc4
The point here is to force the queen trade to defuse white's attack. If white would insist on 25. Qh6?? then 25... Qe3+ forcing a queen trade, resulting in black being an exchange up and the white attack drying out. So, white takes the knight instead, and forces black to make the queen trade on better terms.
25. Bxc4 Qe3 26. Qxe3 Rxe3
Both white bishops are hanging, but a counter-threat will save them.
27. Bd4 Re7
After the attack has been defused, white has now two bishops for a rook and a pawn. White makes one more piece sacrifice, but this time it is a temporary one to win two pawns.
28. Bxd5 cxd5 29. Nxd5 (diagram)
The threat of Nf6 winning the piece back is unstoppable, and black's intermezzo check does not change matters.
|Position after 36... Rcc2|
29... Rc8+ 30. Kb1 Re2 31. Nf6+
The knight cannot be taken, as 31... Nxf6 32. Bxf6 threatening mate with Rh8#. The only move to stop the immediate mate is 32... Re1+ giving up a rook.
31... Kf8 32. Nxh7+ Ke7
For the engines, winning the rook-bishop-knight vs rook pair pawn endgame is merely a technicality. Without pawns, this would be draw. The simple plan for white is to use the material advantage to create a passed pawn.
33. Ng5 Rc4 34. Rd1 b4 35. Ne4
Cuts the rook on e2 from the black's side of the board, and also creates a simple mating threat with Bf6+ and Rd8#.
35... Kd7 36. b3 Rcc2 (diagram)
This may look superficially dangerous for white, but as long the white minor pieces control squares on the 2nd rank to create escape squares for the king, there are no immediate mate or 3-fold threats by black. So, white has now time to win the f7-pawn.
|Position after 49. f6|
The king cannot save the f-pawn, for 37... Ke8 is a forced mate: 38. Nf6+ Ke7 39. Rd7+ Kf8 40. Rd8+ Kg7 41. Rg8+ Kh6 42. Bf4#
37... Kc6 38. Rd8 Kb6 39. Rb8+
Final subtle point, winning a tempo on the king when taking the f7-pawn. The direct attack would ruin white's win: 39. Rf8 Rc6 40. Rxf7?? and black will force the draw by repetition with Re1+/Re2+.
The black king is forced to go to a7, as 39... Kc6 Rc8+ would win a rook, and 39... Ka5 40. Bd6 would be a forced mate in 12 more moves (the immediate threat is Bxb4# and the white king escapes the checks by the black rooks on d1.
39... Ka7 40. Rf8 Rc6 41. Rxf7+ Kb6 42. Rd7
Now the white rook would break the three-fold by intercepting at the d2-square.
42... Re1+ 43. Kb2 Rc8 44. Rd2 Rf1 45. Bd4+ Kc6 46. Rc2+ Kd5
Black finally gave up and went chasing for the f-pawns with the king.
47. Rxc8 Kxd4 48. Nd2 Rh1 49. f6 1-0. (diagram)
White wins by the TCEC win rule.
The position is a forced mate. For example: 49... Rh7 50. Rf8 Ke5 51. Ne4 Rh3 52. Ng5 Rh2+ 53. Kc1 Kf5 54. f7 Rh6 55. Rg8 Rc6+ 56. Kd2 Rd6+ 57. Ke3 Rf6 58. f4 Rxf7 59. Nxf7 Ke6 60. Ne5 Kd5 61. Rg6 a5 62. Nc6 Kc5 63. Ne7 Kb5 64. Kd4 a4 65. Nd5 axb3 66. Nc7+ Ka5 67. Ra6#
- https://lichess.org/Mmbuujxk#17 (accessed on 2020-03-01)