TCEC Season 18 This is not a SuFi Bonus Game 39: LeelaCPU-Stockfish

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http://talkchess.com/forum3/viewtopic.php?f=2&t=72084&hilit=grob&start=410

Game overview

1. g4

End of the opening book. The Grob opening (1. g4) is rated by the strongest engines as the worst first move. It is sometimes seen by the titled players as a surprise blitz weapon, and in rapid games to a lesser degree. But the opening is practically never seen in a serious game with classical time controls, as its practical merits are hard to justify.

For the opening move, the current SF-dev evaluation is at around -1.1 at depth 56 (330B nodes) and the Leela T42810 evaluation is at expected score of around 33%. Contrasting, the evaluation for the common first moves are at around +0.5 for Stockfish and at around 53-55% for Leela, respectively. The opening does not do any better in the opening database, black winning a bit more than half the time. Needless to say, 1. g4 is not a great opening move by any standard.

The opening has been recently debated at the TalkChess.com forums using deep engine analysis, the question being whether it is objectively still drawn for white. The most recent studies claim that Stockfish with depth 60 analysis would not be able hold the draw against a correspondence-level preparation by black, favoring the argument that 1. g4 is losing against best play.

In the game, black responds with the most principled move, attacking the g4-pawn immediately.

1... d5 2. Bg2 Bxg4 3. c4

Fritz gambit makes the Grob gambit more like a temporary pawn sacrifice. It will be difficult for black to keep the pawn advantage. That said, exchanging g-pawn to a queen-side pawn is not exactly great.} 3... c6 { [%csl Gb7,Gc6,Gd5]} 4. Qb3 { [%csl Gc6][%cal Gb3b7,Gg2a8] Leela plays the Grob opening in an aggressive manner, trying posing some immediate problems for black for the pawn.} 4... e6 { With e6, black keeps the white fianchetto bishop out of play.} ( { In Nakamura-Mamedyarov, https://www.chessgames.com/perl/chessgame?gid=1963060 ( TC: 15m+2spm ) : } 4... Qd7 5. cxd5 Nf6 6. Nc3 cxd5 7. Nxd5 Nc6 )( { The engines' second choice } 4... Nf6 5. Qxb7 Nbd7 )5. Qxb7 Nd7 6. Nc3 ( { The c6 pawn was not freeing, and taking it can be dangerous, as black would get more initiative } 6. Qxc6 $2 Rc8 7. Qa6 Rxc4 8. Na3 ( 8. Nc3 Qc7 { The white queen would start to feel stranded, there is the threat of e4 for winning the bishop on c1 with no counterplay to speak of.} )8... Rc8 )6... Ne7 7. cxd5 exd5 8. d4 Rb8 9. Qa6 ( { Not a free pawn. Black either gets the d4-pawn in exchange, or worse } 9. Qxa7 $2 Nf5 10. Nf3 ( 10. e3 Nh4 11. Kf1 )10... Ra8 11. Qb7 Bxf3 12. exf3 ( 12. Bxf3 $2 Nxd4 { fork threat that cannot be really parried} 13. Bf4 ( 13. O-O) 13... Nc5 14. Qc7 Qxc7 15. Bxc7 Nc2+ )12... Nxd4 )9... Rb6 10. Qd3 Ng6 11. h3 { Typical for Leela, fighting for counterplay} 11... Be6 12. Nf3 Bd6 13. h4 h6 $146 { https://lichess.org/NlyX5cNC#25 Black prevents white from playing Ng5 immediately.} ( { In Ohtake-Parsons (Correspondence game from 2014): ½-½ } 13... O-O 14. b3 Qf6 15. Kf1 h6 16. h5 Bf5 17. Qd1 Nf4 )14. Bh3 { White forces the exchange of the bad bishop and tries to mount some counterplay on the open king-side. But it is a bit double-edged, as it also exchanges a defender and puts a stop on hopes of king safety.} 14... Bxh3 15. Rxh3 O-O { [%cal Gc1d2,Ga1g1]} 16. h5 Ne7 17. Rh1 c5 { Logical for black to start opening the position to further take advantage of better development. This also creates the threat of c4, which white immediately discourages.} 18. b3 Qc8 19. Na4 Rc6 20. dxc5 Ne5 { The intermezzo allows black to develop the bishop to a better square with tempo. The tempo is used to maneuver Rc6-e6 for putting pressure on the e-file.} ( 20... Nxc5 21. Nxc5 Rxc5 )21. Nxe5 Bxe5 22. Rb1 Re6 23. Bd2 Re8 24. Rc1 Nc6 { Now that the rooks are doubled on the semi-open e-file, white's king safety is being seriously questioned. Black has multiple additional resources to add to attack, as the light pieces are centralized and the untouchable d5-pawn controls important squares, and is ready to advance. White king sidesteps the rook battery.} 25. Kf1 ( { Taking the d5-pawn would be a huge mistake. For example: } 25. Qxd5 Rd8 26. Qg2 Qd7 27. Rd1 Bf4 28. e3 Qd3 29. Nb2 Qc2 30. Nc4 Nd4 { White's position is beginning to crumble} )25... Bd4 26. Nc3 Rf6 27. Rh2 Re5 28. Nb5 Qg4 { [%cal Ga2a6,Gb3b6][%csl Ga2,Gb3,Ge2,Gf2]}

29. Nxd4 { White tries to relieve some of the pressure, but there white's

defenses are getting overloaded.} ( { The threat: } 29. a4 Rxh5 30. Rxh5 Rxf2+ 31. Ke1 Qg1# )29... Nxd4 30. Rg2 Qh4 31. Qg3 { White enforces the queens off the board with the immediate Qxg7# threat. However, black wins material in the tactics afterwards} ( { The threat by black } 31. Re1 Rxf2+ 32. Rxf2 Qh1# )31... Qxg3 32. Rxg3 Nxe2 { Wins a pawn and forks the rooks} 33. Rgc3 Nxc3 34. Rxc3 Rc6 { [%csl Gh5][%cal Gd5d3]} 35. b4 Rxh5 36. Ke2 { [%cal Gh5h4,Gh4c4]} 36... f6 { Makes room for Kf7-e6 and supports g5 later on, and goes for a sharp pawn race} ( { Here black had multiple ways to convert the game. Perhaps the easiest would have been to stop all white queenside counterplay and then start pushing with the kingside pawns: } 36... d4 37. Rc4 Rh3 38. Rxd4 Ra3 39. Rd8+ Kh7 40. Be3 a6 { As now the white qside pawns are blockaded, at least for the time being, black would have plenty of time to start pushing the king-side pawns.} )37. Kd3 Rc8 38. Be3 Rh4 39. f4 { Natural move to prevent the black rook attacking b4. A similarly natural response would be to either play g5, intending to create connected passers, or Rh1 to start attacking the white pawns from behind and to make room for the h-pawn push. However, black goes for a faster conversion with the rush of getting the h-pawn promoted.} 39... h5 ( 39... g5 40. fxg5 hxg5 )40. c6 Rh1 41. b5 h4 42. Bxa7 h3 43. b6 h2 44. b7 Re8 45. Kc2 { [%cal Ge8e2,Gh1c1]} ( { Even if the pawns on 7th look menacing, and even winning, white is simply not in time } 45. c7 Rhe1 46. b8=Q h1=Q 47. Kd4 Qe4+ 48. Kc5 Rb1 49. a3 Qe1 50. Rb3 Qe7+ 51. Kc6 Qe6+ 52. Kc5 Rc1+ 53. Kb5 Qd7+ 54. Kb6 Rc6+ 55. Kb7 Rxb8+ 56. Bxb8 d4 57. f5 Rc1 { White can't both stop the d-pawn advancing and Qc6+ mating} 58. a4 Qc6+ 59. Ka7 Qxa4+ 60. Kb7 Qc6+ 61. Kc8 Re1 )45... Rc1+ { Cute little tactic to exchange to rook for a queen.} 46. Kxc1 h1=Q+ 47. Kb2 d4 48. Bxd4 Qd5 { The dangerously looking bc pawns are now dynamically blockaded. Any attempt to pust them would lose them. Black uses the better mobilitity of the heavy pieces to overrun white and with material-winning threats.} 49. Be3 Kf7 50. a4 ( 50. c7 Qxb7+ )50... Rh8 51. Rc2 Qe4 { Forking the bishop and the a4-pawn.} 52. Bd2 Qxa4 53. Rc3 ( 53. c7 Qb5+ )53... Qd4 54. Be3 ( 54. Kc2 Rh2 55. b8=Q Qxd2+ 56. Kb3 Qb2+ 57. Kc4 Qxb8 )54... Rh2+ 55. Kb3 Qd5+ 56. Rc4 Qd3+ ( 56... Qb5+ 57. Rb4 Rb2+ ( 57... Qd3+ 58. Ka4 Ra2# )58. Kxb2 Qxb4+ 59. Ka2 Qa4+ ( 59... Ke6 60. Ba7 Qa4+ 61. Kb2 Qxa7 )60. Kb2 )57. Kb4 ( 57. Rc3 Qb5+ 58. Ka3 Rb2 { M4} )57... Rb2+ 58. Kc5 Ke6 { Threat: Qd6#} 59. Rb4 Qd5+ 60. Kb6 Rxb4+ 61. Ka7 Ra4+ 62. Kb6 Qa5# 0-1