TCEC Season 16 Superfinal Game 26 – Stockfish-AllieStein
|Game||Season 16, Superfinal, Game 26|
|Links|| TCEC archive|
|Position after 16. h4|
1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Bb4+ 6. Bd2 Be7 7. Nc3 O-O 8. Qc2 Na6(N)  9. a3 c5
End of book. The book exit is following a game by AlphaZero and Stockfish.
10. d5 exd5 11. Ng5 Nc7 12. Nxd5
This is where the game deviated from the AlphaZero-Stockfish game. AlphaZero played the immediate 12. h4, which is a move that could have also been played by Leela with the Jhorthos T40B.4-160 net, with both the game continuation and the AlphaZero move being close in evaluation.
12... Ncxd5 13. cxd5 d6 14. e4 b5 15. f4 h6 16. h4 (diagram)
White is threatening to win a piece with e5. Black cannot take the knight on g5, as it would dangerously open black for an attack. Example line: 16... hxg5 17. hxg5 Ng4 18. e5 g6 19. e6 b4 (to stop Bc3) 20. exf7+ Kg7 21. O-O-O a5 22. Rde1 Qd7 23. Re6. The concrete threat is now Qxg6 and black has to start sacrificing pieces (e.g., Qxe6) to avoid getting mated.
If the threat is ignored, white could simply take a piece. For example: 16... a6 17. e5 dxe5 18. fxe5 g6 19. exf6 Bxf6 20. Ne4.
16... b4 17. axb4 cxb4 18. e5 dxe5 19. fxe5 Re8 20. Kd1
The white king sidesteps preemptively off from the e-file to keep the tension.
Taking the piece here would expose white's king for an attack, giving black enough counterplay to likely maintain a draw. For example: 20. exf6 Bxf6+ 21. Kf1 Bxg5 22. hxg5 Bxd5 23. Bxd5 Qxd5 24. Rh2 Rac8
|Position after 21... Nh5|
20... hxg5 21. hxg5 Nh5 (diagram)
Black offers a piece back. Indeed, 22. Rxh5 g6 would allow black to defend against the immediate mate threats. However, white has a strong intermediate move to open up the defenses.
|Position after 25. Ra6|
22. g6 Bxd5 23. Rxh5 Qd7 24. gxf7+ Kxf7 25. Ra6 (diagram)
White offers black a chance to win the exchange with Qg4+. Accepting the exchange sacrifice is black's best option, as black does not have good defensive options to deal with mating threats such as Qg6+ without losing material decisively. For instance, 25... Be6 26. Rxe6 Qxe6 27. Bh3 and if the black queen moves away, then mate is immediate, e.g., 27... Qb6 28. Qc4+ Kg6 29. Bf5+ Kxh5 30. Qg4#.
Note that taking the bishop on g2 would lose material after the e6+ fork.
|Position after 28. Rh6|
25... Qg4+ 26. Kc1 Qxh5 27. Bxd5+ Kf8 28. Rh6 (diagram)
If the black queen evades, Rh8# is coming. Black also cannot take the rook, as 28... gxh6 29. Qf5+ and black would lose the queen to avoid getting mated immediately: 29... Qxf5 30. Bxh6#.
So, black decided to give up the queen, as there are no better options.
28... g6 29. Rxh5 Rec8
Seemingly, black is now pinning the queen, but white can simply follow with a rook check to turn the tables. Note that 29... Rac8 could not have been played, instead, due to the immediate 30. Bh6# mate threat.
30. Rh8+ Kg7 31. Rxc8 Rxc8 32. Qxc8 Bg5 33. Qg8+ Kh6 34. Qh8# 1-0.
Black has been mated.
GM Sadler, Matthew. The TCEC16 Computer Chess Superfinal: a perspective. https://tcec-chess.com/articles/Sufi_16_-_Sadler.pdf
- https://lichess.org/SE1uj5Pk#15 (accessed on 2019-11-17)
- GM Sadler, Matthew. The TCEC16 Computer Chess Superfinal: a perspective. https://tcec-chess.com/articles/Sufi_16_-_Sadler.pdf