Steamrolling the king

by ChessBase
6/15/2021 – There are sacs, and there are sacs. This turn of phrase that suggests not all are the same could not be more true of piece sacs in chess. Some are just flat out blitzkrieg tactics to gain material or reach for the jugular, but this one was a long-term attacking sac by Fat Fritz 2 that took no fewer than 20 moves to convert, with many a deep idea as demonstrated in this article. Not to be missed!

Fat Fritz 2 Fat Fritz 2

Fat Fritz 2.0 is the successor to the revolutionary Fat Fritz, which was based on the famous AlphaZero algorithms. This new version takes chess analysis to the next level and is a must for players of all skill levels.

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The players and conditions

In a deep match on top-of-the-line hardware, Fat Fritz 2 faced a special configuration of Leela, using its best and largest neural network inside a fast binary called Ceres, all while enjoying a dual GPU system that housed an RTX 3080. The RTX 3080 is practically a unicorn these days due to the bitcoin resurgence, and as a result sells for around $2000 on average. Fat Fritz 2 ran on a 14-core Intel CPU, and both were playing a rapid time control of roughly 35 mins. 

The Game

As is typical of such matches, the engines were provided the basic opening moves to set up the start, after which they were entirely on their own. In theory, Leela should enjoy an edge in this phase as the neural networks are notoriously strong in the opening, but Fat Fritz 2 is a different animal, even in the NNUE world. What makes it different is that instead of training on a traditional engine positions and evaluation set to a fixed depth as Stockfish's NN was, Fat Fritz 2 was actually trained on Fat Fritz 1.0 games, positions, and evaluations. For the Leela net aficionados, these were all at 1600 nodes/position, double what is typical for this level of data creation. So its opening knowledge is taken from Fat Fritz 1.0, though whether this will be enough to counter the much larger neural network it faces is up for debate.

 

This was the last book move provided for the engines. This positions makes its firs appearance in Mega 2021 in a game in 1957 with none other than Najdorf playing it with black, but it is still popular and recent players taking up the gauntlet with black include teen phenom GM Alireza Firouzja and GM Amin Bassem from Egypt. A number of continuations exist here, with the most popular being 10. Re1, but Fat Fritz 2 prefers the second choice...

 

This powerful shot first saw regular play by the Bulgarian master Kiril Ninov in the 1970s and 1980s, but it failed to get any traction, and it wasn't until 1990 when Yussupov played it against Kasparov that it caught the collective attention of grandmasters. Though Yussupov lost that day, Huebner came back in 1992 in Dortmund, and defeated the very same Kasparov with it. Karpov then became its next more serious proponent in the mid 1990s when he played it in the Amber tournaments. Even last year in the Cap d'Agde event, Bulgarian GM Cheparinov played it twice against Indian GM Bassem with each scoring a win. 

After 10...dxc5 11.dxe5 ♘e8 White played 12.e6

 

Though a good case can be made for 12.♘a4, this was the choice of Karpov, Huebner, and even Carlsen. Wait, Carlsen played this too? Sure, and of course we are referring to ... Torben Carlsen, the correspondence grandmaster! The point it fairly clear, the pawn is a goner anyhow, so why not use it to weaken Black's position?

Five moves later, this position presented itself.

 

The move is 17.e5! While Black does enjoy a beautifully centralized bishop, now it has been cut off from the kingside, which is starting to look like a piece of swiss cheese with those gaping holes in the dark squares.

For the record, this very position with 17.e5 was reached by GM Carlsen (Torben) in 2007 in an email tournament. It ended in a draw.

Fast forward the position until move 23 when White just played 23.♖f3-g3

 

The position is beginning to look almost catastrophic. Black's two bishops may be 'sweeping' the board, but they are biting dust and are cut off from where the action is really taking place. White is threatening to continue to build up the position with h4, ♗e4, ♘f3, etc. For lack of good options, Black played 23...h6 and was served up with the powerful sac that set in motion the end.

 

Here Fat Fritz 2 played 24.♘xe6!! and while other engines may indeed find it too, it brings to mind the quote by the late Rudolf Spielmann who once said that he could find every combination that Alekhine found. The problem wasn't finding the combinations but setting up those positions!

Speaking of which, by all means play the move on the diagram above to see how it looks.

After 24...♘xe6 (forced) 25.♕xg6+ ♘g7 26.♗e4 we can see why this looks so attractive. 

 

There is no immediate win or return of material, but White's initiative here is crystal clear. White continued to position his pieces and build up the attack while Black tried to organize a defense, until this position was reached after 32 moves. 

 

Can you guess what White played here? It is without question far from obvious. White played the astonishing move 33.♗h4!! 

In fact, this move deserves a diagram.

 

At first glance this move can seem so odd that one asks oneself whether this is some really odd computer move bringing to mind the strange plays in the pre-AlphaZero age, where the oddest moves would be justified by reams of calculations and billions of nodes, but otherwise inexplicable.

No, this not some tactical nuke dropped in Black's position, it is in fact a deep positional idea. The point here is that White plans to play ♕h7+, a  move that has been threatening for 10 moves now, followed by the g-pawn with g6, which opens the diagonal for the ♗h4, and prepares ♘f6. A beautiful concept, which explains the paradoxical looking 33rd move.

The play continued until move 41, when a cute last tactic presented itself:

 

This move invites Black to fall on his sword, since Bxd3 leads to mate after Qh8+. The game is clearly over though they played on until move 56.

Game with replayer

[Event "?"] [Site "?"] [Date "????.??.??"] [White "Fat Fritz 2"] [Black "Ceres 0.89-J94-100"] [Result "1-0"] [ECO "E69"] [PlyCount "111"] {[%evp 0,111,29,29,29,5,37,37,37,9,14,14,14,1,33,22,58,9,38,23,23,34,43,43,43, 0,0,-4,-2,-31,-11,-23,-23,-34,-33,-33,22,15,11,-7,1,-10,-12,1,-14,-22,-16,-33, 197,83,90,90,90,90,149,49,102,-26,118,-49,21,60,0,-162,34,-66,-33,-15,-15,2,2, 2,2,2,71,57,40,-14,64,-11,-18,-83,-143,-189,59,59,59,13,13,13,198,129,209,209, 363,363,363,509,509,509,509,436,509,437,576,644,624,636,881,881,881,1041,1119, 880]} 1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 d6 5. Bg2 O-O 6. O-O Nbd7 7. Nc3 e5 8. e4 c6 9. h3 Qb6 {This was the last book move provided for the engines. Even today one can find games by players such as Firouzja and Amin Bassem as black.} 10. c5 $1 {[#] This powerful shot first saw regular play by the Bulgarian master Kiril Ninov in the early 1980s, but it failed to get any traction, and it wasn't until 1990 when Yussupov played it against Kasparov that it caught the collective attention of grandmasters. Though Yussupov lost that day, Huebner came back in 1992 in Dortmund, and defeated the very same Kasparov with it. Karpov then became its next more serious proponent in the mid 1990s when he played it in the Amber tournaments.} dxc5 11. dxe5 Ne8 12. e6 {Though a good case can be made for 12...Na4, this was the choice of Karpov, Huebner, and even Carlsen. Wait, Carlsen played this too? Sure, and of course I am referring to ... Torben Carlsen, the correspondence grandmaster!} fxe6 13. Ng5 Ne5 (13... Nc7 14. f4 Bd4+ 15. Kh1 Nf6 16. e5 Nfd5 17. Qe1 Bd7 18. Rf3 Rae8 19. Bd2 c4 20. Nge4 Qxb2 21. Rb1 Qc2 22. Rc1 Qb2 23. Nd6 Nb5 24. Nxc4 Bxc3 25. Nxb2 Bxb2 26. Rb1 Bd4 27. a4 Nbc7 28. Rxb7 c5 29. Ba5 Rc8 30. Rd3 Rfd8 31. Rxa7 { 1-0 (31) Karpov,A (2780)-Nunn,J (2630) Monte Carlo 1995}) 14. f4 Nf7 15. Nxf7 Bd4+ 16. Kh2 Rxf7 17. e5 {[#] The point is clear. While Black does enjoy a beautifully centralized bishop, the kingside is starting to look like swiss cheese with gaping holes in the dark squares.} Qc7 (17... Nc7 18. Ne4 Nd5 19. a4 a5 20. Ra3 Qc7 21. Ng5 Rf8 22. h4 b6 23. Be4 Qg7 24. h5 h6 25. Nf3 Ba6 26. Nxd4 cxd4 27. Rf2 gxh5 28. Qxh5 d3 29. Bd2 Rad8 30. Qh3 Kf7 31. Rb3 Bc4 32. Bxd5 Bxd5 33. Rxb6 Rb8 34. Rxb8 Rxb8 35. f5 exf5 36. Qxf5+ Kg8 37. Rf4 Rf8 38. Qxd3 Rxf4 39. Bxf4 Qg4 40. Kg1 h5 41. Kh2 Kf7 {1/2-1/2 (41) Carlsen,T (2641) -Blanco Gramajo,C (2562) ICCF email 2007}) 18. Ne4 b6 19. Ng5 Rf8 20. Qc2 Ng7 21. g4 Ba6 22. Rf3 Rad8 23. Rg3 {The position is beginning to look almost catastrophic. Black's two bishops may be 'sweeping' the board, but they are biting dust and are cut off from where the action is really taking place. White is threatening to continue to build up the position with h4, Be4, Nf3, etc.} h6 {[#] Although it does not take an oracle to see the result the future holds, how it unfolds is still quite startling.} 24. Nxe6 $3 {The theme of castle destruction could be epitomized by this example.} Nxe6 25. Qxg6+ Ng7 26. Be4 Rfe8 27. Be3 Bc4 28. Re1 Bxb2 {Before criticizing this pawn grab, ask yourself what Black can do.} (28... Bf7 29. Qxh6 Re6 30. Qh7+ Kf8 {And White's position almost plays itself.}) 29. Rg2 Bd4 30. g5 h5 31. Bf2 Re7 32. Bg3 Qc8 { [#] Can you guess what White played here?} 33. Bh4 $1 {At first glance this seems like some return to those completely crazy moves by engines in the past, which held up to all the tactics, but made anything but sense. However, this seemingly incomprehensible move actually has a very straightforward plan behind it. White's plan is Qh7+, followed by g5-g6 and with the diagonal open for the bishop, then Bf6!} Qe6 34. Qh7+ Kf8 35. g6 Rdd7 36. Qh6 Bc3 37. Rc1 Bd4 38. Bf6 Rc7 39. Rd2 Red7 40. Re1 Ke8 41. Bd3 $1 {This move invites Black to fall on his sword, since Bxd3 leads to mate after Qh8+} Bd5 42. f5 Qg8 43. Bh4 Qf8 44. f6 {[#] It certainly makes for a striking image.} Be6 45. Qg5 Rd5 46. Bc4 Nf5 47. Bxd5 cxd5 48. f7+ Kd7 49. Qd8+ Qxd8 50. Bxd8 Rc8 51. f8=Q Rxd8 52. g7 Bc3 53. Rf2 Bxe1 54. Rxf5 Bxf5 55. Qxf5+ Kc7 56. Qf7+ 1-0

 

 

 


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