testposition from the topboard of the candidates

[Thomas Lagershausen]

[d]4k2r/p2n1pp1/1rn1p2p/q2pP2P/PRpP4/2P5/2QBNPP1/5RK1 w - - 3 23

23.f2-f4 !

Did a machine play this great move?

[pgn][Event "FIDE Candidates 2020"]
[Site "Yekaterinburg RUS"]
[Date "2020.03.25"]
[Round "7"]
[White "Vachier Lagrave, M"]
[Black "Nepomniachtchi, I"]
[Result "1-0"]
[BlackElo "2774"]
[ECO "C18"]
[Opening "Französische Verteidigung"]
[Variation "Winawer-Variante, 6...Ne7 7.h4 Qc7"]
[WhiteElo "2000"]
[TimeControl "40/3600:40/3600:40/3600"]
[Termination "normal"]
[PlyCount "83"]
[WhiteType "program"]
[BlackType "human"]

1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. a3 Bxc3+ 6. bxc3 Ne7 7. h4 Qc7 8.
h5 h6 9. Rb1 b6 10. Qg4 Rg8 11. Bb5+ Kf8 12. Bd3 Ba6 13. dxc5 Bxd3 14. cxd3
Nd7 15. d4 bxc5 16. Qd1 Qa5 17. Bd2 Rb8 18. Ne2 c4 19. O-O Rb6 20. Qc2 Rh8
21. a4 Ke8 22. Rb4 Nc6 23. f4 Ne7 24. Rfb1 f5 25. Rb5 Qa6 26. Bc1 Kf7 27.
Ba3 Rhb8 28. Bxe7 Kxe7 29. g4 Rxb5 30. axb5 Rxb5 31. gxf5 Rxb1+ 32. Qxb1
exf5 33. Ng3 Qb6 34. Nxf5+ Kf8 35. Qa1 Qe6 36. Ng3 Qg4 37. Kg2 Qxf4 38.
Qxa7 Ke7 39. Qa3+ Kd8 40. Qd6 g5 41. hxg6 h5 42. g7 1-0
[/pgn]

[zullil]

[d]4k2r/p2n1pp1/1rn1p2p/q2pP2P/PRpP4/2P5/2QBNPP1/5RK1 w - - 3 23

23.f2-f4 !

Did a machine play this great move?

[pgn][Event "FIDE Candidates 2020"]
[Site "Yekaterinburg RUS"]
[Date "2020.03.25"]
[Round "7"]
[White "Vachier Lagrave, M"]
[Black "Nepomniachtchi, I"]
[Result "1-0"]
[BlackElo "2774"]
[ECO "C18"]
[Opening "Französische Verteidigung"]
[Variation "Winawer-Variante, 6...Ne7 7.h4 Qc7"]
[WhiteElo "2000"]
[TimeControl "40/3600:40/3600:40/3600"]
[Termination "normal"]
[PlyCount "83"]
[WhiteType "program"]
[BlackType "human"]

1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. a3 Bxc3+ 6. bxc3 Ne7 7. h4 Qc7 8.
h5 h6 9. Rb1 b6 10. Qg4 Rg8 11. Bb5+ Kf8 12. Bd3 Ba6 13. dxc5 Bxd3 14. cxd3
Nd7 15. d4 bxc5 16. Qd1 Qa5 17. Bd2 Rb8 18. Ne2 c4 19. O-O Rb6 20. Qc2 Rh8
21. a4 Ke8 22. Rb4 Nc6 23. f4 Ne7 24. Rfb1 f5 25. Rb5 Qa6 26. Bc1 Kf7 27.
Ba3 Rhb8 28. Bxe7 Kxe7 29. g4 Rxb5 30. axb5 Rxb5 31. gxf5 Rxb1+ 32. Qxb1
exf5 33. Ng3 Qb6 34. Nxf5+ Kf8 35. Qa1 Qe6 36. Ng3 Qg4 37. Kg2 Qxf4 38.
Qxa7 Ke7 39. Qa3+ Kd8 40. Qd6 g5 41. hxg6 h5 42. g7 1-0
[/pgn]

Game is already a win for White:

info depth 35 seldepth 59 multipv 1 score cp 279 nodes 1804499954 nps 34103149 hashfull 329 tbhits 0 time 52913 pv b4b6 d7b6 f1a1 b6c8 d2c1 c8e7 a1b1 a5d8 c1a3 d8a8 c2b2 e8d7 b2b7 a8b7 b1b7 d7c8 b7e7 c6e7 a3e7 c8d7 e7d6 h8c8 g2g4 g7g6 h5g6 f7g6 e2f4 g6g5 f4h5 d7e8 h5f6 e8f7 f6d7 c8h8 g1g2 h6h5 g4h5 h8h5 a4a5 g5g4 d7f6 h5h3 d6b4 a7a6 f6g4 h3d3 g4f6 d3d2 g2g3

[Thomas Lagershausen]

Maybe, but the human move is the shortest way to a full point.

It looks like that human topchess is still the most interesting chess.

[zullil]

Maybe, but the human move is the shortest way to a full point.

It looks like that human topchess is still the most interesting chess.

23. f4 is not even one of the top three moves, according to Stockfish:

info depth 40 seldepth 65 multipv 1 score cp 310 nodes 25755457876 nps 33194685 hashfull 990 tbhits 0 time 775891 pv b4b6 d7b6 f1a1 a5a6 d2c1 e8d7 f2f4 b6c8 a1b1 c8e7 c1a3 f7f5 e5f6 g7f6 f4f5 e7f5 e2f4 c6d8 a3c5 d8b7 b1e1 b7c5 d4c5 a6c6 f4e6 h8e8 c2f5 e8e6 g1h1 d7e7 f5h7 e7d8 e1b1 e6e7 h7h6 d8d7 h6f4 c6c5 f4f6 c5e3 b1b7 d7e8 f6c6 e8f7 c6g6 f7f8 b7b8 e7e8 g6f5 f8g7 b8b1 e3e7 b1f1 e7h4 h1g1 e8e1 f5f8 g7h7 f8f7 h7h8

info depth 40 seldepth 77 multipv 2 score cp 238 nodes 25755457876 nps 33194685 hashfull 990 tbhits 0 time 775891 pv f1b1 b6a6 b1a1 c6b4 c3b4 a5d8 b4b5 a6b6 d2a5 h8f8 a5b6 d8b6 c2h7 b6a5 h7g7 a5d2 g1f1 e8d8 g7g3 d2b2 a1e1 d8e7 g3h4 e7e8 h4f4 f8h8 f4g3 e8f8 g3e3 b2b4 e1a1 b4b2 e3a3 b2a3 a1a3 f8e7 f2f4 h8a8 a4a5 a8b8 e2c3 f7f6 a3a1 b8g8 c3e2 g8b8 a1b1 b8f8 f1e1 f6e5 f4e5 e7d8 b1a1 d8c7 e1d2 f8f2 a1g1

info depth 40 seldepth 67 multipv 3 score cp 235 nodes 25755457876 nps 33194685 hashfull 990 tbhits 0 time 775891 pv b4b1 c6e7 b1b6 a7b6 d2c1 d7b8 c1a3 b8c6 f2f4 a5a7 g2g4 f7f5 e2g3 h8f8 g4f5 e7f5 a3f8 f5g3 c2g6 e8f8 g6g3 c6e7 f1a1 a7a5 a1a3 e7f5 g3g6 f8e7 g6g2 a5a8 a3a1 e7f8 g2h2 f8f7 h2b2 a8d8 b2f2 d8a8 f2e1 a8a7 e1d2 a7a5 a1a3 a5a7 a3a2 a7e7 d2e1 e7a7 a2a1 a7a8 g1f2 a8d8 e1h1 d8a8 h1d1 a8d8 d1g4 d8a8 g4g6 f7e7 g6g1

Presumably, it appears better than it is due to poor play by Black. Here's Stockfish's evaluation when forced to consider 23. f4:

info depth 43 seldepth 96 multipv 1 score cp 210 nodes 12053263904 nps 34856674 hashfull 779 tbhits 0 time 345795 pv f2f4 c6e7 b4b6 d7b6 f1a1 f7f5 e5f6 g7f6 f4f5 e6e5 c2b1 b6d7 d4e5 f6e5 f5f6 a5c5 g1h1 d7f6 b1b8 c5c8 b8e5 h8f8 a1e1 c8f5 e5f5 e7f5 e2g3 f5e7 d2h6 f8g8 e1f1 f6g4 h6c1 e7c8 c1a3 e8d7 h1g1 c8d6 a3c5 a7a5 c5b6 g8g5 b6a5 g4e3 f1f3 e3g4 a5b4 g4e5 f3f6 d6f7 g3f5 g5h5 f5e7 h5h6 f6h6 f7h6 e7d5 h6f5 g1f2 d7e6 d5c7 e6d7 c7b5 e5d3 f2f3

[Thomas Lagershausen]

Ok, this is a individual opinion for this position.

But what is the value of this opinion?

We have no access to the opinion of Magnus Carlsen and Alpha Zero.

[jp]

We do have Carlsen's opinion. We also have access to Leela's (and Leela has superior performance to A0).

What was it that convinced you this move was so great?

[zullil]

Ok, this is a individual opinion for this position.

But what is the value of this opinion?

We have no access to the opinion of Magnus Carlsen and Alpha Zero.

Lc0 agrees with Stockfish that f4 is not one of the top three moves:

Nodes: 2.5M, N/s: 5.6k, Time: 7m 24s

83.6% Rxb6 Nxb6 Ra1 Kd7 Bc1 Nc8 Rb1 Nb6 Kh2 Kc8 Ra1 Nd7 Ba3 Qd8 Rb1 Na5 g3 Qg5 Nf4 Nb3 Bd6 a5 Rxb3 cxb3 Qxb3 Qd8 c4 Qb6 Qc3 dxc4 Qxc4+ Kb7 Qd3 Rc8 Qf3+ (N: 2.4M, WDL: 714 245 41, P: 18.77%)

79.4% Rbb1 Kd8 Rxb6 Nxb6 Ra1 Kd7 Bc1 Nc8 Rb1 Nb6 Ba3 Kc8 Bc5 Qxa4 Qc1 Rd8 Kh2 Nd7 Bd6 Nb6 f4 Na5 (N: 80.5k, WDL: 639 309 52, P: 13.51%)

79.8% Rfb1 Nxb4 cxb4 Qa6 b5 Qc8 Bb4 Qd8 Nc3 f5 a5 Rb7 b6 Kf7 Nb5 Kg8 Nd6 Rb8 bxa7 Ra8 Qa4 Rxa7 (N: 13.1k, WDL: 659 277 64, P: 5.16%)

[Ovyron]

Maybe, but the human move is the shortest way to a full point.

Believe me, as chess is concerned this claim of yours would be one of the hardest things to prove, if true.

[Thomas Lagershausen]

The moves are shown by stockfish are not convincing.

For example 24.Rxb6?

So i have two questions:

A) What is the defence of the machine against 24.g4 !? with the plan of Ng3 and pawn f5?

B) How improves the machine the black play after MVL's 24.Rfb1?

[jp]

Again, what was it that convinced you this move was so great?