Leela and the Golden Star

Leela Chess Zero – Stockfish

Top Chess Engine Championship Season 17 — Superfinal; match game 92; tcec-chess.com, April 20, 2020

Two Knights Defence C57

With an imperious crescendo, Leela Chess Zero put an end to Stockfish’s claim. After 95 games, it (she) leads by 49½ – 45½, virtually winning the match with still 5 games to go. 1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 Bc5!? A desperate Stockfish goes for the crazy Traxler Variation, maybe because AI imitates humans. 5. Bxf7+ Ke7 6. Bc4. 6. Bb3 and 6. Bd5 are the usual continuations here, but probably Stockfish’s “theoretical licence” is not new either. 6. ... Qe8 7. Nc3 Nd4 8. d3 d6 9. Nd5+ Nxd5 10. Bxd5 Qg6 11. c3 h6 12. cxd4 Bxd4

13. f4! exf4 14. Nf3 Qxg2 15. Rf1 Bh3 16. Qe2 Qxe2+ 17. Kxe2 Bxf1+ 18. Kxf1 Bf6 19. d4! Rhd8. 19. ... g5 20. e5 does not look more inviting. 20. Bxf4 c6 21. Bb3 Rf8 22. Ke2 Bxd4 23. Bxd6+ Kxd6 24. Nxd4 Rf4 25. Bc2 Re8

26. Rg1. Now, after 26. ... g5 27. Ke3 White would enjoy a clear, safe and healthy advantage. Then Stockfish — as humanely as possible — tried its luck in an endgame a Knight down for two Pawns: 26. ... Rexe4+ 27. Bxe4 Rxe4+ 28. Kd3. Machines, however, do not believe in miracles, and Leela Chess Zero mercilessly capitalised on its material advantage by winning in other 102 moves (!). 28. ... Ke5 29. Nf3+ Kf4 30. Ne1 Re7 31. Ng2+ Kg5 32. Ne3+ Kh5 33. Rg3 Rd7+ 34. Ke2 Re7 35. Rh3+ Kg6 36. Rf3 c5 37. Rf4 b5 38. Kf3 Rd7 39. Ke2 Re7 40. b3 Re6 41. Rg4+ Kf6 42. Rf4+ Kg6 43. Rf2 h5 44. Kd3 Rd6+ 45. Ke4 Re6+ 46. Kf3 Rf6+ 47. Kg2 Re6 48. Nd5 Kh6 49. Nc7 Rg6+ 50. Kf3 a6 51. Rc2 Rc6 52. Nd5 Kg5 53. Kg3. Now, White is threatening to win a Pawn by Nd5-b4. Black can only delay the inevitable. 53. ... c4 54. bxc4 bxc4 55. Ne3 c3 56. Nd1. The run is over, and, with it, the game. 56. ... Rd6 57. Nf2 Rd4 58. Rxc3 Ra4 59. a3 Kf6 60. Rf3+ Ke6 61. Nd3 Rg4+ 62. Kf2 Rc4 63. Nf4+ Kd6 64. Kg3 Rc5 65. Re3 Rg5+ 66. Kf3 Kc6 67. Ne6 Rg6 68. Nf4 Rg5 69. h3 Ra5 70. Ke4 Kd7 71. Rc3 Ke7 72. Nd3 Kf6 73. Nc5 Rb5 74. Nxa6 Re5+ 75. Kf3 Re1 76. Nb4 Rf1+ 77. Kg2 Re1 78. Kf2 Re4 79. Kf3 Rh4 80. Kg3 Rd4 81. Rd3 Rc4 82. Kf2 Kg5 83. Nd5 Re4 84. Nc3 Re8 85. a4 Ra8 86. Rd4 Kg6 87. Kg3 Ra6 88. Rc4 Kh6 89. Kf4 Rf6+ 90. Kg3 Rg6+ 91. Kh2 Ra6 92. h4 Kg6 93. Kg3 Ra5 94. Kf4 Rf5+ 95. Ke4 Ra5 96. Rd4 Rc5 97. Kd3 Rf5 98. Ke3 Re5+ 99. Re4 Rc5 100. Kd4 Rf5 101. Nd5 Rf1 102. Ke5 Kh7 103. Ne3 Rf8 104. Rc4 Ra8 105. Kf4 Kg6 106. Nd5 Ra5 107. Nb6 Kh6 108. Rd4 Ra7 109. Rb4 Rf7+ 110. Kg3 Rf5 111. Rb5 Rf1 112. a5 Rg1+ 113. Kh2 Ra1 114. Kg2 Ra2+ 115. Kg3 Kg6 116. Nc4 Ra1 117. Rc5 Kf6 118. Rxh5 Kg6 119. Rc5 Rg1+ 120. Kf2 Ra1 121. Rc7 Kh6 122. h5 Ra4 123. Rc5 Ra2+ 124. Kf3 Ra1 125. Ke2 Kh7 126. h6 Kxh6 127. Kf2 Kg6 128. Rc7 Kh7 129. Rc5 Ra2+ 130. Kf3 1 : 0.

The Meg

Leela Chess Zero – Stockfish

Top Chess Engine Championship Season 17 — Superfinal; match game 88; tcec-chess.com, April 20, 2020

King’s Indian Defence E91

Naw, Leela Chess Zero didn’t fall in love, and mercilessly re-established distances immediately. 1. e4 g6 2. d4 c6 3. c4 d6 4. Nc3 Nd7 5. Be2 Ngf6 6. Nf3 Bg7 7. 0-0 0-0 8. Be3 a6 9. h3 b5 10. Qc2 Qc7 11. cxb5. Leela Chess Zero brings its own brand of charm to a line which was already very favourable to White: 11. Rac1 Bb7 12. Nd2 Rac8 13. f4 bxc4 14. Nxc4 d5 15. Ne5 dxe4 16. Nxe4 Nxe4 17. Qxe4 Nf6 18. Qd3 Nd5 19. f5 f6 20. Ng4 g5 21. Nf2 e6 22. fxe6 Qe7 23. Nd1 Rcd8 24. Bg4 f5 25. Bxf5 Nxe3 26. Nxe3 Bxd4 27. Rce1 c5 28. Kh1 Kh8 29. Qc2 Bc6 30. a4 Bxe3 31. Rxe3 Rd4 32. Re5 Bxa4 33. Qxc5 Rd6 34. Rd5 Rxe6 35. Qd4+ Qg7 36. Qxa4 Qxb2 37. Qd7 Rh6 38. Rd6 Qe2 39. Rfd1 Rh4 40. R6d2 Qe5 41. Rd5 Qf6 42. Qc7 Qf7 43. Qxf7 Rxf7 44. Be6 1 : 0 谭中怡 (Tán Zhōngyí) – 黄茜 (Huáng Qiàn), 4th China Women Masters Tournament, 无锡 (Wúxī) 2014. 11. ... cxb5 12. Rfc1 Qd8. Maybe b8 was a better place. 13. Nd2 Nb6 14. Bf3 Ne8 15. b3 Bb7 16. a4 b4 17. Ne2 a5 18. Qd1 e6 19. Rc2 Nf6 20. Rac1 Rb8 21. Qf1 Ba6 22. Qd1 Rc8 23. Nf4 Rxc2 24. Rxc2 Nfd7 25. Be2 Bb7 26. Bb5 Nf6 27. f3 Nc8 28. Qc1 Na7 29. Bd3 Qb8 30. Nc4 Nc6 31. Nb6 Ne7 32. Bb5 g5 33. Ne2 h6 34. Kh1

34. ... Ng6. Now, since after this Stockfish goes into a desperate ending without even a shadow of hope, it may come natural to suggest something like 34. ... Nc8 35. Nc4 Na7 36. Nxa5 Nxb5 37. axb5 Ba8 38. h4 Bxe4!? 39. fxe4 Nxe4 with two Pawns for the Knight and a little air — but, of course, what is tricky for humans is hardly a worry for machines. 35. Rc7 Ne8 36. Bxe8 Rxe8 37. Nd7 Qa8 38. Ng3 Re7

39. d5! Qe8 40. Rxb7 Rxd7 41. Qc6 Rd8 42. Ne2 Rc8 43. Qxe8+ Rxe8 44. dxe6 fxe6 45. Bb6 Rc8 46. Rc7 Ra8 47. Kg1 Ra6 48. Bd4 Be5 49. Kf2 h5 50. g3 Ra8 51. Be3 d5 52. Ra7 Rxa7 53. Bxa7 dxe4 54. Bb6 exf3 55. Kxf3 Kf7 56. g4 Ba1 57. gxh5 Ne5+ 58. Ke3 Nc6 59. Kd3 Ne5+ 60. Kc2 Nc6 61. Be3 Bf6 62. Ng3 Bd4 63. Bxg5 Be5 64. Ne2 Bd6 65. Kd3 Ne5+ 66. Ke4 Nd7 67. Kd4 Nc5 68. Kc4 Ne4 69. Be3 Bf8 70. Kd3 Nf6 71. Bb6 Nd5 72. Bxa5 Ke7 73. Kc4 Kd7 74. Nd4 Bg7 75. h6 Bxh6 76. Bxb4 Ne3+ 77. Kd3 e5 78. Ne2 Nd1 79. Be1 Bf8 80. Nc3 Nb2+ 81. Kc2 Nxa4 82. bxa4 Kc8 83. Kd3 Kb7 84. Ke4 Ka8 85. Kxe5 Kb7 86. Ne4 Bg7+ 87. Kf5 Ka6 88. Bc3 1 : 0.

The Fish Who Found the Sea

Stockfish – Leela Chess Zero

Top Chess Engine Championship Season 17 — Superfinal; match game 87; tcec-chess.com, April 19, 2020

King’s Indian Defence E94

Thanks to a powerful win in the 87th game of its match with Leela Chess Zero, Stockfish reduced the gap to a single point. 1. e4 g6 2. d4 c6 3. c4 Bg7 4. Nc3 d6 5. Be2 Nf6 6. Nf3 0-0 7. 0-0 e5 8. d5 Na6 9. Be3 Ng4 10. Bg5 f6 11. Bh4 c5 12. a3 Nh6 13. h3!? Stockfish’s una tantum code, in alternative to the manoeuvre Nf3-e1-d3, with which Vladimir Borisovich Kramink won a model game against Loek van Wely in the 72nd Corus Chess Tournament at Wijk aan Zee in 2010. 13. ... b6 14. Qd3 Nf7 15. Rfb1 h5 16. Bd1 Rb8 17. b4 Bh6 18. Rb3 Rb7 19. Qe2 Ng5 20. Nh2 Rh7 21. Rab1 Nf7 22. Nb5 Qe7 23. f3 Kh8 24. Bc2 Rg8 25. Nf1 Bf4 26. Qf2 g5 27. Bg3 Nh6 28. Ne3 Qf8 29. Bd3 Bd7 30. Rf1 Qg7 31. Qe1 Nf7 32. Be2 Qh6 33. Nf5 Bxf5 34. exf5 g4 35. Bxf4 exf4 36. h4 Rhg7 37. Kh1 Re8 38. Qd2 Re7 39. Bd1 Rg8 40. Re1 Re5 41. Nxa7 Rge8 42. Rf1 Re3 43. Rc3 Rxc3 44. Qxc3 Re3 45. Qd2 g3. Black has a Pawn less and its Queenside is on the verge of ruin, but, in true King’s Indian style, nothing is lost yet — even if by a hair. 46. Nc6

46. ... Qf8? This might be the losing move. 46. ... Ne5! 47. Nd8 (47. b5 Nc7 48. a4 Qf8! 49. a5 Qe8! seems to hold as well) 47. ... Qh7! 48. Ne6 Nxc4 49. Qc1 b5∞ was unclear but probably balanced. 47. Re1! Ne5

48. Rxe3! Nxc4 49. Qe2! Nxe3 50. Qxa6 Nxd1 (50. ... Nxd5 51. Qb7!+−) 51. Qxb6 Ne3. 51. ... cxb4 is even worse, if possible, than the text: 52. axb4 Ne3 (52. ... Nc3 53. Qd4+−) 53. b5 Nxd5 54. Qa5+− winning handily. 52. b5 Nxd5 53. Qd8 Qxd8 54. Nxd8 c4 55. Ne6 c3 56. Nd4 Nb6 57. Kg1. The endgame is won by force. 57. ... Kg7 58. Kf1 Kf7 59. Ke2 Nd5 60. Kd3 Ke7 61. a4 Kd7 62. a5 Kc7 63. b6+ Kc8 64. Kc4 Ne3+ 65. Kxc3 Nxg2 66. a6 Ne3 67. b7+ Kc7 68. Nc6 Kxc6 69. b8=Q g2 70. a7 Nd5+ 71. Kd3 Nc7 72. a8=Q+ Nxa8 73. Qxa8+ Kb6 74. Qg8 Kc5 75. Qxg2 d5 76. Qc2+ Kb6 77. Kd4 Kb7 78. Kxd5 Kb6 79. Qc6+ Ka5 80. Qb7 Ka4 81. Kc4 Ka5 82. Qb5 mate.

Thought Outdanced

Stockfish – Leela Chess Zero

Top Chess Engine Championship Season 17 — Superfinal; match game 83; tcec-chess.com, April 19, 2020

Sicilian Defence B40

Leela Chess Zero is still leading by two points, but, beyond mere numbers, today Stockfish exhibited itself in all its splendour. 1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Qb6 5. Nb3 a6 6. Nc3 d6 7. Bf4 Nf6 8. Qd2 Be7 9. 0-0-0 0-0 10. f3. Perhaps for pride, Stockfish just adds its own byte to a game which is featured in Natasha Regan’s and Matthew Sadler’s book “Game Changer” (New In Chess, Alkmaar, 2019) as an example of AlphaZero’s attacking style: 10. g4 Nxg4 11. Rg1 Ne5 12. Qe2 Qc7 13. Be3 b5 14. f4 Nc4 15. Bd4 g6 16. Qh5 Nd7 17. Qh6 Bf6 18. Rd3 Bxd4 19. Nxd4 Re8 20. Rh3 Nf8 21. e5 d5 22. Bd3 Nxe5 23. fxe5 Qxe5 24. Qh4 Bb7 25. Rf3 Rac8 26. Nce2 Rc7 27. Rf6 Ree7 28. Kd2 Red7 29. a3 Kg7 30. Nf4 Rc8 31. Rg5 Qc7 32. Nfxe6+ Nxe6 33. Rxe6 Qa5+ 34. b4 Qxa3 35. Nf5+ Kg8 36. Ne7+ Rxe7 37. Rxe7 Qc3+ 38. Ke2 d4 39. Qf4 1 : 0 J. Polgár – Short, 25th Sparkassen Chess Meeting, Dortmund 1997. 10. ... Rd8. In the following, reverse game there followed 10. ... Ne8 11. h4 Qc7 12. Bg5 b5 13. Bxe7 Qxe7 14. h5 Nc6 15. h6 g6 16. Nd4 Bb7 17. a3 Na5 18. Bd3 Qc7 19. Rhe1 Rc8 20. Nb3 Nc4 21. Bxc4 bxc4 22. Nd4 e5 23. Nde2 Rb8 24. Qe3 f6 25. Rd2 Rf7 26. Nd1 Qc6 27. Nec3 Nc7 28. Qe2 Rc8 29. Ne3 Ne6 30. Red1 Qc5 31. Kb1 Nd4 32. Qf1 Ne6 33. Qf2 Bc6 34. Qe2 Bb7 35. Ka2 a5 36. Ned5 Nd4 37. Qe3 Rb8 38. Na4 Qa7 39. Nab6 Bxd5 40. Nxd5 Kf8 41. c3 Nb3 42. Qxa7 Rxa7 43. Rc2 Kf7 44. Ne3 with White winning a Pawn and finally forcing Black to resign after other 143 moves (!), Leela Chess Zero – Stockfish, Top Chess Engine Championship Season 17 — Superfinal, April 19, 2020, match game 84. 11. g4! Qc7 12. g5 Ne8 13. h4 b5 14. Be3 Nd7

15. g6! hxg6 16. h5 b4 17. Ne2 Ne5 18. Ned4 a5 19. hxg6 Nxg6 20. Qh2 Bf6 21. Bd3 a4

22. e5! axb3 23. exf6 Nxf6 24. Nxb3 Bb7

25. Bh6! Bxf3 26. Bxg7! Nh5 27. Bf6! Qa7 28. Bg5 Rdc8 29. Rdf1 Bg4 30. Rfg1 Bf3 31. Qh3! Qb7 32. Nd4 b3 33. a3 Rxa3 34. bxa3 bxc2 35. Qxf3 Qb1+ 36. Kd2 Qb2 37. Nxc2 Qc3+ 38. Kd1 Qb3 39. Rxh5 Rxc2

40. Rh8+! Nxh8 41. Bh7+ Kxh7 42. Qxb3 Rg2 43. Rxg2 Ng6 44. Bf6 d5 45. Qh3+ Kg8 46. Qh8 mate.

Drawing the Human Figure

Stockfish – Leela Chess Zero

Top Chess Engine Championship Season 17 — Superfinal; match game 77; tcec-chess.com, April 18, 2020

Chigorin Defence D07

Stockfish has finally won a game. 1. d4 d5 2. c4 Nc6 3. Nf3 Bg4 4. cxd5 Bxf3 5. gxf3 Qxd5 6. e3 e5 7. Nc3 Bb4 8. Bd2 Bxc3 9. bxc3 Qd6 10. Qb3. This is also (but not only!) an inversion of moves with 10. Rb1. 10. ... Nge7?! Leela Chess Zero pursues a very dubious opening policy, by sacrificing a Pawn for no objective compensation. Probably best is 10. ... 0-0-0 (in order to transpose into known theoretical lines with 11. Rb1 b6) against which Grandmaster Alexander Sergeyevich Morozevich recommends 11. Be2 f5 (11. ... Nge7?! 12. Qxf7±) 12. 0-0 Nge7 13. Rfb1 b6 14. a4↑ with White’s initiative going unchallenged. 11. Qxb7 0-0. A rapid chess game between Sergei Yuryevich Shipov (White) and Morozevich (Black) at Moscow in 1992 continued: 11. ... Rb8 12. Qa6 0-0 (12. ... Qg6!? 13. Qd3 f5 14. d5 e4) 13. Bd3! Rb2 and now, instead of 14. Bc1?, White should play 14. Rd1! f5 (14. ... Qd5 15. Be4 Qxa2 16. Qxa2 Rxa2 17. Ke2 Rb8 18. Rb1 is even worse) 15. Bc1 Rb6 16. Ba3± with a clear advantage (Morozevich’s analysis). 12. Rd1!? This “mysterious” Rook move is also a novelty in place of 12. Qb3 as in Orság – Pisk, 18th Czech Chess Championship, Ostrava 2010. 12. ... Rab8 13. Qa6 Rb6 14. Qc4 Rfb8 15. Bd3 exd4 16. cxd4 Nb4 17. Be4 Nbd5 18. Rc1 Qe6 19. Bxd5 Nxd5 20. e4 c6 21. Be3 Nxe3 22. Qxe6 fxe6 23. fxe3 c5 24. dxc5 Rb2

25. 0-0 Rxa2 26. Rf2 Ra6. Exchanging a pair of Rooks with 26. ... Rxf2 27. Kxf2 a5 should not make any difference for the better, since once the a-Pawn and the c-Pawn have disappeared, there arises the same ending as after White’s 42th move. 27. c6 Rc8 28. c7 Kf7 29. h4 Rb6 30. h5 Rb7 31. Rfc2 a5 32. Kf2 a4 33. f4 h6 34. Ke2 a3 35. e5 Ke7 36. Kf3 Rb2 37. Rc4 a2 38. Ra1 Rh2 39. Ke4

39. ... Rb2? Of course, 39. ... Rxh5?? 40. Rxa2+− is totally hopeless. However, Black’s best option was 39. ... Kf7 — here is a sample variation (though anything but forced): 40. Kd4 g6! 41. hxg6+ Kxg6 42. e4 h5 43. Rc6 Kf7 44. f5 Re2 45. Kd3! Rh2! (45. ... Rg2? 46. Rxe6 Rxc7 47. Rh6 Kg7 48. Rxh5 Rcc2 49. Rg5+!+−) 46. Rxe6 Rxc7 47. Ra6 Rh3+ 48. Kd4 Rd7+ 49. Kc5 Rc3+ 50. Kb4 Rdc7 with a draw. 40. Ra4+− Rxc7 41. R1xa2 Rxa2 42. Rxa2 Rc4+. 42. ... Kf7 43. Ra6! also leaves Black no way but resignation. 43. Kd3 Rc7 44. Ra6 Rd7+ 45. Kc4 Rc7+ 46. Kd4 Rd7+ 47. Kc5 Rd5+ 48. Kc6 Kf8. Or 48. ... Rd3 49. Ra7+ Kf8 50. f5 winning as in the game. 49. e4 Rd4 50. f5 Kf7 51. Kc5 Rxe4 52. Ra7+ Kf8 53. Ra8+ Ke7 54. Ra7+ Kf8 55. fxe6 Re1 56. Rf7+ Ke8 57. Rxg7 Rc1+ 58. Kd5 Rd1+ 59. Kc5 Rc1+ 60. Kd5 Rd1+ 61. Ke4 Rf1 62. Ra7 Rf2 63. Rh7 Re2+ 64. Kf5 Rf2+ 65. Kg6 Re2 66. Rb7 Ra2 67. Kxh6 Ra6 68. Kg7 Ra1 69. h6 Rh1 70. h7 Rg1+ 71. Kh8 Rg2 1 : 0.

Heartbyte

Leela Chess Zero – Stockfish

Top Chess Engine Championship Season 17 — Superfinal; match game 66; tcec-chess.com, April 17, 2020

King’s Indian Defence E94

Leela Chess Zero lengthened its pace as it (she) won the 66th game, thus taking a 3-point lead over Stockfish. 1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Be2 0-0 6. Nf3 e5 7. 0-0 exd4 8. Nxd4 Re8 9. f3 Nc6 10. Nc2 Nd7 11. Be3 Bxc3. Stockfish ventures itself into a controversial line of theory. 12. bxc3 b6!? That’s the new move — but not much of an improvement on 12. ... Nc5 13. Qd2 Be6 14. Nb4⩲/± Miladinović – Gelashvili, 1st International Chess Open, Korinthos 1997. 13. Nb4 Na5 14. Bh6 Nc5 15. Qd4 Ne6 16. Qf2 c6

17. Rae1! Now Leela Chess Zero takes off into a sequence of “mysterious” Rook moves, in spite of its having access to two open files! 17. ... Nc5 18. h4! Qf6 19. Rc1 Bd7 20. Rfe1 Nab7 21. Nd3 Nxd3 22. Bxd3 Qe5 23. Rcd1 f6. If 23. ... Qxc3 then 24. Bc1! taking over the long diagonal a1–h8. 24. Bc2 Nd8 (24. ... Qxc3 25. Be3!)

25. c5! A powerful breakthrough at the cost of a Pawn. 25. ... Nf7. 25. ... bxc5 26. f4 is a worse version of the game. 26. Bc1 bxc5 27. f4 Qe6 28. c4 Rab8 29. h5! gxh5 30. Qh4 Qg4 31. Qxf6 Re6 32. Qc3 Rg6 33. Rd2 Qg3

34. Re3! Qxf4 35. e5! Nxe5 36. Bxg6 hxg6 37. Rxe5 Qxe5 38. Qxe5 dxe5 39. Rxd7. An asymmetrical endgame has arisen, in which White has an extra Bishop for three Pawns. Formally, Black’s compensation is sufficient, but its Pawns are too weak and shattered not to fall. 39. ... Rb1 40. Rd1 Rb4 41. Bg5 Rxc4 42. Rd6 Rg4 43. Bf6 Re4 44. a3. 44. Rxc6 Kf7 may eventually transpose into the game. 44. ... c4. 44. ... Ra4 45. Bxe5 Rxa3 46. Rxg6+ Kf7 47. Rxc6 echoes the game’s mainstream. 45. Rxc6 Kf7 46. Bg5 Re1+ 47. Kh2 Ra1 48. Rxc4 Rxa3 49. Rc7+ Ke6 50. Rc6+ Kf7. If 50. ... Kf5 then 51. Be7 followed by Rc6-f6+xg6. 51. Rf6+ Kg7 52. Re6 Ra5 53. Re7+ Kf8 54. Rc7 Ra4 55. Bh6+ Ke8 56. Rg7. Now either the a-Pawn or the g-Pawn must fall. 56. ... Rh4+ 57. Kg1 a5 58. Rxg6 Kf7 59. Ra6 a4 60. Bg5 Rg4 61. Bd8 Rc4 62. Bf6 Rc5 63. Bh8 Kg8 64. Ra8+ Kh7 65. Kh2 Rd5 66. Kg3 a3 67. Bf6 Rd3+ 68. Kh4 Kg6 69. Be7 Rd2 70. Bxa3 Kf7. Unluckily for Black, the g2-Pawn is taboo. Now Leela Chess Zero pursues its last dance with exemplary technique. 71. Kh3 Rd1 72. Kh2 Kg6 73. Bc5 Rd2 74. Re8 Re2 75. Bd6 Kf6 76. Rh8 Rd2 77. Bb8 Rb2 78. Ba7 Kg6 79. Rb8 Ra2 80. Bc5 Kf5 81. Rh8 Kg4 82. Rg8+ Kf4 83. Bd6 Rd2 84. Be7 Rd7 85. Bh4 e4 86. Bg5+ Kf5 87. Be3 h4 88. Bf2 Rd3. Or 88. ... Rh7 89. Kh3 then capturing the Pawn anyway. 89. Bxh4+− Rd7 90. Rd8 Rb7 91. Bf2 Ke6 92. Re8+ Kd5 93. Be3 Kc4 94. Rxe4+ 1 : 0.

Lemniscate

Stockfish – Leela Chess Zero

Top Chess Engine Championship Season 17 — Superfinal; match game 35; tcec-chess.com, April 13, 2020

Sicilian Defence B79

And finally — so far — Leela Chess Zero took the lead over Stockfish, even though the best game of the day was a pyrotechnic draw: 1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 g6 6. Be3 Bg7 7. f3 0-0 8. Qd2 Nc6 9. Bc4 Qa5 10. 0-0-0 Bd7 11. Bb3 Ne5 12. Kb1 Rfc8 13. h4 h5 14. Bg5 Kf8. In the following, reverse game Stockfish opted instead for 14. ... b5 which yielded White a lasting edge in the endgame after 15. Nd5 Qxd2 16. Rxd2 Kf8 17. Nxf6 exf6 18. Bf4 a5 19. a3 Kg8 20. Rhd1 Bf8 21. Ne2 Kg7 22. Rd4 Ra7 23. Bd2 Nc6 24. Rd3 Rb8 25. Bd5 b4 26. Rb3 Ra6 27. Be1 bxa3 28. Rxb8 Nxb8 29. b3 Nc6 30. Nd4 Ne7 31. Bf2 Kg8 32. Ka2 f5 33. c4 fxe4 34. fxe4 Nxd5 35. exd5 Be7 36. Kxa3 Kf8 37. g3 Bd8 38. Nb5 f6 39. Rf1 Kf7 40. Kb2 Kg8 41. Bd4 g5 42. Rh1 gxh4 43. Rxh4 Bg4 44. Rh1 Kg7 45. Na7 Kf7 46. Nc6 Ra8 47. Re1 Bd7 48. Nxd8+ Rxd8 49. Bb6 Rg8 50. Bxa5 Rxg3 51. Bc7 Rg2+ 52. Kc3 Rg3+ 53. Kb4 Rd3 54. Bxd6 Bg4 55. Rg1 f5 56. Rg3 Rd4 57. Kc5 Re4 58. Rd3 h4 59. Rd4 Re8 60. b4 Rc8+ 61. Kb6 Re8 62. b5 Be2 63. Rxh4 Kf6 64. c5 Rd8 65. Kc7 Rg8 66. b6 Rg7+ 67. Kb8 Bf3 68. Rd4 Rg8+ 69. Ka7 Rg1 70. b7 Ra1+ 71. Kb6 Rb1+ 72. Kc6 Bg2 73. b8=Q Rxb8 74. Bxb8 f4 75. Rxf4+ Kg5 76. Rg4+ Kxg4 1 : 0 Leela Chess Zero – Stockfish, Top Chess Engine Championship Season 17 — Superfinal, April 13, 2020, match game 36. 15. g4!? hxg4 16. h5 Rxc3! 17. h6! Bh8 18. h7! Rc5 19. Bh6+ Ke8 20. Qxa5 Rxa5

21. Bg7! Nxh7 22. Bxh8 Nf8 23. Bg7 g5 24. Bxf8 (24. Rh8 Ng6=) 24. ... Kxf8 25. Rh8+ Kg7 26. Rxa8 gxf3. A fantastically unbalanced position has arisen on the board — Black has three Pawns (of which two are Kingside passers) for a Rook.

27. Kc1 Bh3! 28. Rd2 e6 29. Rf2 g4 30. Kd2 Bg2 31. Ke3 Nd7! 32. Rd8 Nf6 33. Rxd6 Re5

34. Nxe6+! fxe6 35. Rxe6 Rxe6 36. Bxe6 g3 37. Rxf3 Bxf3 38. Kxf3 g2 39. Kxg2 Nxe4 40. Bd5. The most White’s got is a drawish Bishop vs. Knight endgame a Pawn up. 40. ... Nd6 41. Kf3 Kf6 42. Kf4 a5 43. Bf3 Ke6 44. Ke3 b6 45. Kd3 Ne8 46. a3 Kd6 47. Kc4 Nc7 48. a4 Ke6 49. b3 Kd6 50. c3 Kd7 51. Be4 Kd6 52. Bb7 Kd7 53. b4. And, finally, this Pawn exchange produces a book draw! 53. ... axb4 54. cxb4 Kd6 55. Kd4 Ne8 56. Bf3 Nc7 57. Be4 Na6 58. Kc4 Nc7 59. Kc3 Ne8 60. Kc4 Nc7 61. Bb7 Kd7 62. Kd3 Ne8 63. Bf3 Kd6 64. Kd4 Nc7 65. Kc3 Ne8 66. Kc4 Nc7 67. Kc3 Ne8 68. Kc4 Nc7 69. Bb7 Kd7 70. Kd3 Kd6 71. Kc3 Ne8 72. Bf3 Kc7 73. Kd4 Kd6 74. Bg2 Nc7 75. Bf3 Na6 76. Kc3 Nc7 77. Kc2 Ne8 78. Bb7 Kc7 79. Bd5 Nd6 80. Kc3 Ne8 81. Be4 Kd6 82. Bg6 Nf6 83. Bf7 Ke7 84. Bb3 Kd6 85. Bc2 Nd5+ 86. Kb3 Nf6 87. Bf5 Kd5 88. Bd3 Kd6 89. Kc4 Kc6 90. Kd4 Kd6 91. Bc4 Ng4 92. Bd5 Nf6 93. Ba8 Ne8 94. Bg2 Nc7 95. Bh1 Ne8 96. b5 Ng7 97. Kc4 Ne6 98. Bf3 Nc5 99. Bd1 Nb7 100. Kb4 Na5 101. Bf3 ½ : ½. A game of theoretical importance.

Critique of Pure Reason

Leela Chess Zero – Stockfish

Top Chess Engine Championship Season 17 — Superfinal; match game 34; tcec-chess.com, April 12, 2020

King’s Indian Defence E69

Surprisingly, or not so surprisingly, after 34 games Leela Chess Zero’s and Stockfish’s scores are still even. 1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 d6 5. Bg2 0-0 6. Nc3 Nbd7 7. 0-0 e5 8. e4 c6 9. h3 Qb6 10. c5 dxc5 11. dxe5 Ne8 12. e6. In the previous, reverse game there followed 12. Na4 Qa5 13. Qc2 Nc7 14. Bd2 Qb5 15. Rfd1 c4 16. Nc3 Qa6 17. Be3 Nxe5 18. Nxe5 Bxe5 19. f4 Bg7 20. g4 Re8 21. Qf2 Nb5 22. Nxb5 Qxb5 23. Bd4 Bxd4 24. Rxd4 Qc5 25. f5 b5 26. Rad1 Ba6 27. a3 Rab8 28. h4!↑/→ Stockfish – Leela Chess Zero, Top Chess Engine Championship Season 17 — Superfinal, April 12, 2020, match game 33. 12. ... fxe6 13. Ng5 Ne5 14. f4 Nf7 15. Nxf7 Bd4+ 16. Kh2 Rxf7 17. e5 Rd7!? The machine’s novelty doesn’t add much to the man’s resourceful defence: 17. ... Nc7 18. Ne4 Nd5 19. a4 a5 20. Ra3 Qc7 21. Nd6 Rf8 22. h4 b6 23. h5 Qg7 24. hxg6 hxg6 25. Be4 Ba6 26. Re1 Ne7 27. Kg2 Rad8 28. Rb3 Bxe5 29. fxe5 Qxe5 30. Qg4 Rxd6 31. Bf4 Rxf4 32. gxf4 Rd2+ 33. Kg3 Qf6 34. Rxb6 Bd3 35. Rb8+ Kf7 36. Qh3 Bxe4 37. Qh7+ Qg7 38. Qxg7+ Kxg7 39. Rxe4 Nf5+ 40. Kf3 Kf6 41. Rc4 Rd5 42. Rf8+ Ke7 43. Ra8 Nd6 44. Rc3 c4 45. Ra6 Rc5 46. b3 Kf6 47. bxc4 ½ : ½ Shirov – Kasparov, 11th Torneo Internacional de Ajedrez Ciudad de Linares, Linares 1993. 18. Qf3 Nc7 19. Ne4 Nd5 20. Rb1 Kh8 21. Bd2 Qa6 22. a3 Qa4 23. h4 b6 24. Bc3 Bxc3 25. bxc3 Ba6 26. Rf2

26. ... Rg7? Clearly not 26. ... Qxa3? 27. Qd1! (Δ Rb1-a1) and Black’s Queen is in danger. The text, however, is rather a strange mistake — and also a strange loss of time. Probably better was 26. ... Re7 27. Nd6 leaving White with excellent compensation for the Pawn. 27. Bh3 Bc8. If 27. ... Nc7 then 28. Nd6 Rf8 29. Rbb2! with consequences very similar to those of the game. 28. Rbb2! c4. If 28. ... Qxa3 there might follow 29. Ra2 Qc1 (after 29. ... Qb3 30. Rfb2 Qc4 31. Bf1 Black’s Queen gets trapped) 30. Rfc2 Qe3 31. Qh1! with great advantage to White. 29. Ra2 b5

30. h5! Qa5 31. h6! Re7 32. Qg4 Qd8 33. Qg5 a5 34. Nd6 Bd7 35. Rac2 Rb8 36. Rc1 Kg8 37. Bg2 Re8. Black’s resolution to give up the Exchange in order to get rid of the monstrous d6-Knight is very human-hearted and emotionally justified, even though the resulting endgame is indefensible and ultimately lost. 38. Nxe8 Bxe8 39. a4 bxa4 40. Ra1 Nxc3 41. Qxd8 Rxd8 42. Rc2 Nd1 43. Rxc4 Ne3 44. Rcxa4 Rd2 45. R1a2 Rxa2 46. Rxa2 Ng4+ 47. Kh3 Nxh6 48. Rxa5 Nf5 49. Ra8 Kf7 50. Ra7+ Ne7 51. Kh4 h6 52. Be4 Kf8 53. Ra8 c5 54. Ra5 c4 55. Rc5 c3 56. Rxc3 Bb5 57. Rb3 Be8 58. Rb8 Kf7 59. Rb7 Kf8 60. Rc7 Bf7 61. Kg4 Ke8 62. Ra7 Kf8 63. Rb7 Be8 64. Rb8 Kf7 65. Kh4 Kf8 66. Ra8 Kf7 67. Ra7 Kf8 68. Ra6 Bf7 69. Kh3 Bg8 70. Kg4 Bf7 71. Kf3 h5 72. Kg2 Be8 73. Rxe6 Kf7 74. Rb6 Bd7 75. Rd6 Bc8 76. Kh2 Kg7 77. Rb6 Kf7 78. Bb7 Bf5 79. Bg2 Kg7 80. Rb7 Kf8 81. Rb2 Ke8 82. Bh3 Be4 83. Bg2 Bf5 84. g4 hxg4 85. Kg3 Be6 86. Be4 Bf5 87. Bxf5 gxf5 88. Kh4 Kd7 89. Kg5 g3 90. Rg2 Nc6 91. Kxf5 Ne7+ 92. Ke4 Nc8 93. Rxg3 1 : 0.

Think tank

Stockfish – Leela Chess Zero

Top Chess Engine Championship Season 17 — Superfinal; match game 33; tcec-chess.com, April 12, 2020

King’s Indian Defence E69

1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 d6 5. Bg2 0-0 6. Nc3 Nbd7 7. 0-0 e5 8. e4 c6 9. h3 Qb6 10. c5 dxc5 11. dxe5 Ne8 12. Na4 Qa5. Back in the90s, the alternative 12. ... Qa6 gained a certain notoriety after a sensational loss by Garry Kimovich Kasparov to Robert Hübner: 13. Bg5 b5 14. Nc3 Nc7 15. Be7 Re8 16. Bd6 Ne6 17. a4 b4 18. Ne2 Qa5 19. Nd2 Ba6 20. f4 c4 21. Kh2 Rad8 22. Qc2 Nb6 23. Rfd1 Bf8 24. Nf3 c3 25. Ned4 Nxd4 26. Nxd4 cxb2 27. Qxb2 Nc4 28. Qb3 Qb6 29. a5 Qb7 30. Bxf8 Kxf8 31. e6 c5 32. e5 Qc7 33. exf7 Qxf7 34. Nc6 Rxd1 35. Rxd1 Nxe5 36. Bd5 Bc4 37. Qc2 Ng4+ 38. hxg4 Re2+ 39. Qxe2 Bxe2 40. Bxf7 Bxd1 41. Bc4 b3 42. Nxa7 b2 43. Ba2 Be2 44. Kg2 Bd3 45. Kf3 Ke7 46. Ke3 b1=Q 47. Bxb1 Bxb1 48. Nb5 Kd7 49. a6 Kc6 50. f5 1 : 0 Hübner – Kasparov, 20th Sparkassen Chess Meeting, Dortmund 1992. 13. Qc2. A novelty, although after 13. Bd2 Qb5 (Kononenko – Kozak, Dnepropetrovsk 2005) White has probably nothing better than to transpose into the actual game with 14. Qc2. 13. ... Nc7 14. Bd2 Qb5 15. Rfd1 c4 16. Nc3 Qa6 17. Be3 Nxe5 18. Nxe5 Bxe5 19. f4 Bg7 20. g4 Re8 21. Qf2 Nb5 22. Nxb5 Qxb5 23. Bd4 Bxd4 24. Rxd4 Qc5 25. f5 b5 26. Rad1 Ba6 27. a3 Rab8

28. h4!↑/→ Bb7 29. h5 gxh5 30. gxh5 Qe5 31. Qh4 c5. Probably a lesser evil is 31. ... h6!? 32. Rd7 Bc8 33. R7d6 Rf8, though after 34. Qh2! Qxh2+ 35. Kxh2 b4 36. axb4 Rxb4 37. R1d2± White will soon regain its Pawn with interest.

32. Rd7 b4. Not 32. ... Bxe4? on account of 33. f6! (threatening Rd1-d5) 33. ... Kh8 34. Re7! winning easily. Instead 32. ... Bc6 33. f6! Kh8 (33. ... Bxd7? 34. Rd5!+−) 34. Rxf7 b4 transposes into the game. 33. f6 Kh8 34. Rxf7 Bc6. Of course, 34. ... Bxe4?? 35. Bxe4 Qxe4 36. Rf8+! is a cheap trick.

35. Rg7!! The winning move (and a most elegant one!), placing Black in a deadly zugzwang. Instead 35. Rxa7 Red8 36. Rf1 Rg8 was still rather unclear. 35. ... c3. There’s no way of avoiding the inevitable: 35. ... bxa3 36. Rg5!+− or 35. ... Qxb2 36. Qg5! Rg8 37. Qh6!+− or 35. ... Rg8 36. h6!+− — Black is inexorably zugzwanged. 36. bxc3 Rf8 37. Rf1 bxc3 38. h6! Threatening Qh4-g4 followed by Rg7xh7+. 38. ... Be8 39. f7! Bxf7 40. Rfxf7 Rxf7 41. Rxf7 c2 42. Rf1 Rg8 43. Rc1 Qd4+ 44. Qf2 Qd1+ 45. Qf1 Qd4+ 46. Kh1 Qd6 47. Rxc2 Qxh6+ 48. Kg1 Qe3+ 49. Qf2 Qxa3 50. Qf6+ Rg7 51. Rb2 Qe3+ 52. Kh1 Qe1+ 53. Bf1 Qxe4+ 54. Kh2 Qe8 55. Bh3 h5 56. Be6 Kh7 57. Qe5 Kh6 58. Rb8 Qxb8 59. Qxb8 h4 60. Qf8 c4 61. Bxc4 h3 62. Bd3 Kh5 63. Qxg7 1 : 0.

A Certain Sum of Days

Stockfish – Leela Chess Zero

Top Chess Engine Championship Season 17 — Superfinal; match game 27; tcec-chess.com, April 11, 2020

2r3k1/q5p1/2b1p2p/n2pPp2/Pp1P4/1P1B1PP1/4NK2/3Q3R w - - 53 72

Position after 71. ... Be8-c6

In the meantime, Leela Chess Zero’s and Stockfish’s scores are still level after 27 very exciting games. In the position of the diagram, White — which needed to win to tie the scores — pulls a rabbit out of the hat: 72. g4!! fxg4 73. Qg1! The hidden pointe behind. 73. ... gxf3 74. Rxh6! Be8. If 74. ... fxe2 then 75. Bh7+ Kh8 (both 75. ... Kf7 and 75. ... Kf8 are refuted by 76. Rf6+!+−) 76. Rh4! Rf8+ 77. Kxe2+− and the curtain falls. 75. Kxf3 Nxb3 76. Rh3 Nd2+ 77. Kg2 Ne4 78. Qh2 Qxa4 79. Rh8+ Kf7 80. Rh7 Kf8 81. Qh3 Qc6 82. Nf4 Bf7 83. Qg4! g5 84. Qf3! gxf4 85. Qxf4 Qc7 86. Rh8+ Ke7 87. Qh4+ Kd7 88. Bb5+ Qc6 89. Bxc6+ Kxc6 90. Rxc8+ Kb5 91. Qe1 Nc3 92. Qa1 Na4 93. Qf1+ Kb6 94. Rb8+ Ka7 95. Qb5 Nb6 96. Qxb6 mate.

LithiumFlash, Infinite chess represented by ASCII character symbols, 2017. Courtesy of Wikimedia Commons.

From its to her

Leela Chess Zero – Stockfish

Top Chess Engine Championship Season 17 — Superfinal; match game 14; tcec-chess.com, April 10, 2020

Modern Benoni A72

The story continues... 1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. Nf3 g6 7. Nd2 Bg7 8. e4 0-0 9. Be2 Nbd7. The previous, reverse game went instead 9. ... Na6 10. 0-0 Nc7 11. a4 Re8 12. f3 b6 13. Nc4 Ba6 14. Bg5 h6 15. Be3 Bxc4 16. Bxc4 a6 17. Qd2 Kh7 18. Rab1 Rb8 19. b4 b5 20. axb5 axb5 21. Be2 Nd7 22. bxc5 Nxc5 23. Nxb5 Nxb5 24. Bxb5 Re7 25. Bd3 Reb7 26. Rxb7 Rxb7 27. Rb1 Rxb1+ 28. Bxb1 Qf6 29. Bc2 Qa1+ 30. Qd1 Qa3 31. Qe2 Qa1+ 32. Qd1 Qa3 33. Bf2 Qc3 34. g3 h5 35. Kf1 Kg8 36. Be1 Qe3 37. Bd2 Qa3 38. Kg2 Bf6 39. Qe2 h4 40. Be3 Nd7 41. Qd3 Qb2 42. Bf2 hxg3 43. hxg3 Qb4 44. Qb3 Qd2 45. Qd3 Qb4 46. Be3 Nc5 47. Qd1 Nd7 48. Qb1 Qc3 49. Qb3 Qa1 50. Qb4 Ne5 51. Bf2 Kg7 52. Qb3 g5 53. Bd1 Qa5 54. Qa4 Qd8 55. Be3 Qc8 56. Qc2 Qd8 57. Qc1 Nd3 58. Qd2 Ne5 59. Be2 Qe7 60. Qc2 Qd8 61. Qd2 Ng6 62. Kg1 Qe7 63. Qb4 Ne5 64. Qb1 Ng6 65. Qc2 Qd8 66. Qc6 Qe7 67. Qc8 Qe5 68. Kf2 Qa1 69. Qc1 Qe5 70. Bd3 Qe7 71. Qc8 Qe5 72. Qc1 Qe7 73. Qc2 Ne5 74. Be2 Ng6 75. Qc8 Qe5 76. Qc2 Qe7 77. Kg2 Qd8 78. Qc4 Qe7 79. Bb6 Qe5 80. Qc2 Qe7 81. Be3 Qd8 82. Qd2 Qe7 83. Qb4 Qc7 84. Qb3 Qe7 85. Qc4 Qd8 86. Bd1 Ne5 87. Qc2 Ng6 88. Be2 Qe8 89. Ba6 Ne5 90. Bd4 Qd8 91. Qc3 Ng6 92. Bc8 Bxd4 93. Qxd4+ Ne5 94. Bf5 Qf6 95. f4 gxf4 96. gxf4 Ng4 97. Qxf6+ Nxf6 98. Kf2 Kf8 99. Ke3 Ke7 100. Bh3 Kd8 101. Kd3 Nh5 102. Ke3 Nf6 103. Bg2 Nd7 104. Kd4 f6 105. Ke3 Nc5 106. Bh3 Ke8 107. Kd4 Kd8 108. e5 fxe5+ 109. fxe5 Nb3+ 110. Kc4 Nd2+ 111. Kd3 Nb3 112. e6 Nc5+ 113. Ke3 Ke7 114. Kf3 Na4 115. Kf4 Nb6 116. Bg2 Kf6 117. Be4 Na8 118. Bd3 Nc7 119. Bc4 Ne8 120. Ke4 Ke7 121. Kd4 Nf6 122. Ke3 Ke8 123. Kd4 Ng8 124. Bb5+ Ke7 125. Bd3 Nf6 126. Bb5 Ng8 127. Bf1 Ke8 128. Bd3 Ke7 129. Ke3 Nf6 130. Kd4 Ng8 131. Bc2 Nf6 132. Ba4 Ng8 133. Kc4 Nf6 134. Bb3 Ng8 135. Bc2 Nf6 136. Bg6 Ng8 137. Kb5 Nf6 138. Kc4 Ng8 139. Kb5 Nf6 140. Kc6 Ng4 141. Be4 Nf6 142. Bf3 Ng8 143. Bd1 Nf6 144. Bf3 Ng8 145. Kb6 Nf6 146. Kb7 ½ : ½ Stockfish – Leela Chess Zero, Top Chess Engine Championship Season 17 — Superfinal, April 10, 2020, match game 13. 10. h3 Ne8 11. 0-0 a6 12. a4 Rb8 13. Nc4 Qe7!? A previous terrestrial game continued as follows: 13. ... Qh4 14. a5 Ne5 15. Nxe5 Bxe5 16. f4 Bd4+ 17. Kh2 Ng7 18. Ra4 f5 19. Rxd4 cxd4 20. Qxd4 fxe4 21. Nxe4 Nf5 22. Qc3 Bd7 23. g3? (23. b3!) 23. ... Qe7 24. Bd3 Rbc8 25. Qe1 Bb5 and soon Black won, Jørgensen – Aagaard, 32nd Politiken Cup, Copenhagen 2010. And since after the text Black wil soon be precipitated into a very unpleasant situation, it may well be worth considering 13. ... Ne5 — after which, incidentally, a draw was agreed in Keresztes – Mészáros, Caissa IM April 2011, Kecskemét 2011. 14. f4 Bd4+ 15. Kh2 Ndf6 16. Bf3 Bxc3 17. bxc3 Nxe4 18. Qe1 f5 19. Nb6 N8f6 20. c4 Bd7 21. Ra3 h5 22. Kg1 Rf7 23. Re3

23. ... a5. Black prefers to give back the Pawn rather than being pythonised by a4-a5. 24. Qxa5 Qd8 25. Bb2 h4 26. Rfe1 Kh7 27. Rb3 Qf8. If 27. ... Ng3 then 28. Re6! Bxe6 29. dxe6 Rf8 30. Re3 with an overwhelming advantage for White. 28. Bxf6 Nxf6 29. Qd2 Qg7 30. a5 Kg8 31. Qf2

31. ... g5. No better is 31. ... Qh6 due to 32. Re6! Bxe6 33. dxe6 Re7 34. Nd5 Nxd5 35. Bxd5 Kg7 36. Bxb7!+− (36. ... Rexb7 37. Qb2+). 32. Nxd7 Nxd7 33. Bh5 Rff8 (33. ... Re7 34. Re6!+−) 34. Re6 Nf6 35. Qe2 Qh6 36. Bf3 g4 37. hxg4 fxg4 38. Bxg4 Qxf4 39. Bh3 Qc1+ 40. Qe1 Qxe1+ 41. Rxe1 Kg7 42. Rb6. White wins a Pawn by force and eventually the game. 42. ... Rfd8 43. Reb1 Ra8 44. Rxb7+ Kg6 45. Ra1 Ra6 46. Rb6 Ra7 47. a6 Kg5 48. Rf1 Nh5 49. Rf5+ Kg6 50. Re5! Nf4 51. Kh2 Kh6 52. Rf5 Nh5 53. Bg4 Ng3 54. Re5 Kg6 55. Bd1 Rf7 56. Bc2+ Kf6 57. Re6+ Kg5 58. Rbxd6 Rxd6 59. Rxd6 Ra7 60. Bd3 Kf4 61. Re6 Kg4 62. Kg1 Kg5 63. Kf2 Nh5 64. Kf3 Nf6 65. Ke3 Ng4+ 66. Kd2 Kf4 67. Be2 Ne5 68. Kc3 Rg7 69. Bf1 Ra7 70. Kb3 Ng4 71. Ka4 Ra8 72. Kb5 Ne5 73. Kxc5 Rc8+ 74. Kd4 Nd7 75. Re7 Nc5 76. a7 Nb3+ 77. Kc3 Nc5 78. Kb4 Ne4 79. g3+ Kf3 80. gxh4 Ra8 81. Bg2+ Kxg2 82. Rxe4 Rxa7 83. d6 Rb7+ 84. Kc5 Rf7 85. Re7 Rf5+ 86. Kb6 1 : 0.

So far, Leela Chess Zero is holding its own in its high noon with Stockfish. Credit: Lc0 Blog.

Dracula and Frankenstein Are Friends

Stockfish – Leela Chess Zero
Top Chess Engine Championship Season 17 — Superfinal; match game 7; tcec-chess.com, April 9, 2020
Vienna Game C27

1. e4 e5 2. Nc3 Nf6 3. Bc4 Nxe4 4. Qh5 Nd6 5. Bb3 Nc6 6. Nb5 g6 7. Qf3 f5 8. Qd5 Qf6. In the following, reverse game there followed 8. ... Qe7 9. Nxc7+ Kd8 10. Nxa8 b6 11. Qd3 Bb7 12. Ne2 Bxa8 13. 0-0 g5 14. Qh3 h5 15. d4 h4 16. c3 f4 17. Bd5 exd4 18. Bxc6 Bxc6 19. Nxd4 Bb7 20. Rd1 Kc8 21. b3 Qf7 22. f3 Bg7 23. Re1 Re8 24. Rxe8+ Qxe8 25. Ba3 Bxd4+ 26. cxd4 Nb5 27. Rc1+ Kb8 28. Bb2 a5 29. Qf5 Qe3+ 30. Kh1 Ka7 31. h3 g4 32. Qxg4 Qd2 33. Qxd7 Qxb2 34. Re1 Nxd4 35. Re7 Qa1+ 36. Kh2 Nxf3+ 37. gxf3 Qxa2+ 38. Kg1 Qb1+ 39. Kf2 Qb2+ 40. Kf1 Qc1+ 41. Ke2 Qb2+ 42. Qd2 Qxb3 43. Qxf4 Qc2+ 44. Ke1 Ka6 45. Qd2 Qb1+ 46. Ke2 Qb5+ 47. Kf2 a4 48. Qd4 Qc5 49. Qxc5 bxc5 50. Ke2 Kb6 51. Kd2 a3 52. Kc3 a2 53. Kb2 Bc8 54. Rh7 Bxh3 55. Rxh4 Bg2 56. f4 Kc6 57. Rh5 Bd5 58. Re5 Bg8 59. Rg5 Bc4 60. Re5 Kd6 61. Re4 Bd3 62. Re3 Bb1 63. Ka1 c4 64. Kb2 Kd5 65. Ka1 c3 66. Rxc3 ½ : ½ Leela Chess Zero – Stockfish, Top Chess Engine Championship Season 17 — Superfinal, April 9, 2020, match game 8. 9. Nxc7+ Kd8 10. Nxa8 b6. A tabiya of the Frankenstein–Dracula Variation.

11. Qf3 Nd4. Maybe best — anachronistically speaking — is 11. ... Bb7 12. h4 Nd4 13. Qh3 Bh6 14. d3 Bxc1 15. Rxc1 e4 16. Ne2? (16. Kf1) 16. ... exd3 17. Nxd4? d2+!−+ 18. Kxd2 Qxd4+ 19. Ke1 Re8+ 20. Kf1 Ne4 21. Kg1 Qxf2+ 22. Kh2 Qf4+ 23. g3 Nxg3! 24. Qxg3 Re2+ 25. Kh3 Bg2+ 26. Qxg2 Re3+ 0 : 1 Vyakhirev – Verlinsky, All-Russian Amateur Tournament, Saint Petersburg 1909. 12. Qh3 f4 13. c3 Nc6 14. d3 h5 15. Qf3 g5 16. Qd1 Ba6 17. Ne2 h4 18. h3 e4

19. 0-0! Who knows, perhaps Black was hoping for a tactical vortex in case of 19. dxe4 Nxe4 20. Bd5 (20. Bc2 Nxf2!! 21. Kxf2 Bc5+ 22. Ke1 Re8 23. Bd3 Bb7! also gives Black excellent compensation) 20. ... Nxf2!! 21. Kxf2 Bc5+ 22. Kf1 Re8 23. Bf3 Rxe2!! (Black will be two Rooks and a Bishop down, but White can’t make any use of it!) 24. Bxe2 f3! 25. Bxa6 fxg2++ 26. Ke2 Qf2+ 27. Kd3 Qf5+ 28. Kd2 Qf2+ drawing by perpetual check. 19. ... Bxd3 20. Bc2 Ba6 21. a4! Bb7 22. a5 Nxa5 23. Ba4 Bxa8 24. b4 Nc6 25. Bxc6 Bxc6 26. Nd4 Bd5 27. Qg4 Nc8 28. Rd1 Rh6 29. Bb2. Despite the dynamic material balance, White is clearly dominating the board. 29. ... Bc4 30. b5 Rh7 31. Nc6+ Kc7 32. Nxa7 Nd6 33. Ba3 Rf7 34. Bxd6+ Bxd6

35. Nc6!! Bxb5. If 35. ... dxc6 then 36. Ra7+ Kb8 (36. ... Kd8 37. Ra8+ Ke7 38. Qc8+−) 37. Ra8+! Kxa8 38. Qc8+ Bb8 39. Ra1+ Ra7 40. Rxa7+ Kxa7 41. Qa6 mate. 36. Nd4 Bd3 37. Ra7+ Kd8 38. Ra8+ Ke7 39. f3 Bc5 40. Rg8 Rg7 41. Rc8 Bxd4+ 42. cxd4 Qg6 43. fxe4 Qxe4 44. Qh5 Qe3+ 45. Kh2 Qg3+ 46. Kh1 f3. Black has nothing better than return one of its two extra Pawns in order to avoid the worst, though, even thus, it has almost zero chances to hold its own in the endgame an Exchange down. 47. Qxf3 Qxf3 48. gxf3 Bb5 49. Rb8 Rf7 50. Re1+ Kd6 51. Rxb6+ Bc6 52. Kg2 Rf4 53. Re4 Rf5 54. Re3 Rd5 55. Rb4 Ra5 56. Rb2 Rd5 57. Rd2 Rf5 58. Rdd3 Rf4 59. Kf2 Bd5 60. Rd1 Be6 61. Re4 Rf5 62. Rde1 Bd5 63. R4e3 Rf4 64. Rg1 Rf5 65. Rg4 Kc6 66. f4 Rxf4+ 67. Rxf4 gxf4 68. Re5 Be6 69. d5+! Bxd5 70. Rh5 Kd6 71. Rxh4 Ke5 72. Rg4 Kf5 73. Rg1 Be4 74. h4 d6 75. Rg8 Ke5 76. h5 Kf6 77. h6 Kf7 78. Rg7+ Kf8 79. Ke2 d5 80. Kd2 Bf5 81. Ke1 Bd3 82. Kf2 Be4 83. Ke2 d4 84. Rg4 Bc2 85. Kf2 Kf7 86. Rg7+ Kf6 87. Rc7 d3 88. h7 d2 89. h8=Q+ Kg6 90. Qg7+ Kh5 91. Rc5+ Kh4 92. Qh6+ Kg4 93. Qh5 mate.

She’s got a dream

Leela Chess Zero – Stockfish

Top Chess Engine Championship Season 17 — Superfinal; match game 4; tcec-chess.com, April 8, 2020

Sicilian Defence B81

1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 d6 6. g4 a6 7. g5 Nfd7 8. Be3. In the previous, reverse game there followed: 8. a3 Nc6 9. Be3 Nde5 10. Be2 Nxd4 11. Qxd4 Nc6 12. Qd2 Be7 13. h4 b5 14. h5 Qa5 15. h6 g6 16. 0-0 0-0 17. f4 Qc7 18. Rf2 Rb8 19. Raf1 Bd7 20. Bg4 Rbc8 21. Bh3 Qb7 22. Na2 a5 23. Nc3 Rb8 24. b4 axb4 25. axb4 Rfc8 26. f5! Ne5 27. fxg6 fxg6 28. Bf4 Rf8 29. Qd4 Qc7 30. Nd5! exd5 31. Bxd7 Qxd7 32. Qxd5+ Nf7 33. Qd4 Bf6 34. Qxf6 Ne5 35. Qg7+!+− Stockfish – Leela Chess Zero, Top Chess Engine Championship Season 17 — Superfinal; April 8, 2020, match game 3. 8. ... b5 9. a3 Bb7 10. f4 Nc6 11. Rg1 Rc8 12. Rg3 Be7 13. f5 Nxd4 14. Qxd4 e5 15. Qd2 Qa5 16. 0-0-0

16. ... Rxc3. Stockfish goes for a very human (as well as thematic) Exchange sacrifice, but without getting any satisfaction except for a Pawn. Such a suggestion is well worth further pursuit! 17. Qxc3 Qxc3 18. bxc3 Bxe4 19. Bd3 Ba8 20. c4 Bc6. 20. ... bxc4 21. Bxc4 Be4 22. Bd3 Bb7 might be just a little better than bad, at least not allowing White a passed Pawn on the a-file. 21. cxb5 axb5 22. c4 bxc4 23. Bxc4 Be4 24. a4! d5. The gain of the second Pawn may cost dear after 24. ... Bxf5 25. a5 0-0 26. Bd5 with White’s Bishops being ready to escort the a-Pawn till a8.

25. Rxd5! Leela Chess Zero gives back the Exchange for a dominant position by virtue of its powerful Bishop pair and passed a-Pawn. 25. ... Bxd5 26. Bxd5 Bb4 27. Rg4 Ba5 28. Rc4 Ke7 29. Rc6 Rd8 30. Bc4 Kf8 31. Bb5 e4 32. Bf4 e3 33. Bxe3 Ne5 34. Ra6 Rc8+ 35. Kd1 Bb4 36. h3 Kg8 37. Ke2 Bc3 38. Rd6 Bb4 39. Rd4 Bc3 40. Rd1 Bb4 41. Rc1 Ra8 42. Rb1 Bc3 43. Rc1 Ba5 44. Bf4 f6 45. Bxe5 fxe5. With the last, faint hope that an opposite-colour Bishop endgame may suddenly materialise itself on the board. Leela Chess Zero, however, is smart enough not to allow that to happen, and slowly but surely forces its opponent to surrender. 46. Rc5 Kf7 47. Kf3 Kf8 48. Rxe5 Bc3 49. Rc5 Bb4 50. Rc4 Ba5 51. h4 Rb8 52. Kg4 Rd8 53. Re4 Bc3 54. Rc4 Ba5 55. Re4 Bc3 56. Kf3 h6 57. g6 h5 58. Re6 Rc8 59. Kg2 Ba5 60. Bd7 Rb8 61. Bc6 Rb2+ 62. Kf3 Rb3+ 63. Ke4 Rb4+ 64. Kd5 Rb8 65. Kc5 Bb4+ 66. Kc4 Ba5 67. Re5 Bc7 68. Re4 Ba5 69. Re6 Rb4+ 70. Kc5 Rb8 71. Re4 Bb6+ 72. Kc4 Ba5 73. Re6 Rb4+ 74. Kd3 Rb3+ 75. Ke4 Rb4+ 76. Kd5 Rb8 77. Bb5 Rc8 78. Re4 Rd8+ 79. Kc4 Rc8+ 80. Kb3 Rc3+ 81. Kb2 Rc8 82. Re6 Rd8 83. Kb3 Rc8 84. Re5 Rc3+ 85. Ka2 Rc2+ 86. Kb1 Rc8 87. f6 gxf6 88. Rxh5 Rc3 89. Rd5 Rc7 90. Bd3 Bb6 91. a5 Be3 92. Kb2 Kg7 93. h5 Kh6 94. Kb3 Bf4 95. a6 Be5 96. Be2 Rc3+ 97. Kb4 Rc7 98. Kb5 Re7 99. Bg4 Bf4 100. Rd7 Re5+ 101. Kc6 Re1 102. g7 Re8 103. Re7 Ra8 104. a7 Be3 105. Rxe3 Kxg7 106. Kb7 Rxa7+ 107. Kxa7 1 : 0. Finally!

Leela Chess Zero ambitiously aims to become the Caïssa of chess engines. Credit: Lc0 Blog.

Antony and Cleopatra

Stockfish – Leela Chess Zero
Top Chess Engine Championship Season 17 — Superfinal; match game 3; tcec-chess.com, April 8, 2020
Sicilian Defence B81

In the meantime, Leela Chess Zero and Stockfish have started today their 100-game Superfinal match, which, even in absence of gender-specific pheromones, promises to be a great love story! 1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 d6 6. g4 a6 7. g5 Nfd7 8. a3 Nc6 9. Be3 Nde5 10. Be2 Nxd4 11. Qxd4 Nc6 12. Qd2 Be7 13. h4 b5 14. h5 Qa5 15. h6 g6 16. 0-0 0-0 17. f4 Qc7 18. Rf2 Rb8 19. Raf1 Bd7 20. Bg4 Rbc8 21. Bh3 Qb7 22. Na2 a5 23. Nc3 Rb8 24. b4 axb4 25. axb4 Rfc8

26. f5! Ne5 27. fxg6 fxg6 28. Bf4 Rf8 29. Qd4 Qc7

30. Nd5! Stockfish provides a powerful refutation of its opponent’s computations. 30. ... exd5 31. Bxd7 Qxd7 32. Qxd5+ Nf7 33. Qd4 Bf6 34. Qxf6 Ne5. This leads to a forced win, but also after 34. ... Nxh6 35. Qxd6 Qxd6 36. Bxd6 Rxf2 37. Bxb8 Rxf1+ 38. Kxf1 Nf7 39. Bf4 the ending is easily won for White. 35. Qg7+! Qxg7 36. hxg7 Rfe8. Or likewise, 36. ... Kxg7 37. Bxe5+ dxe5 38. Rxf8 Rxf8 39. Rxf8 Kxf8 40. Kf2 Ke7 41. Ke3 with a won Pawn ending. 37. Bxe5 dxe5 38. Rf8+! Rxf8 39. Rxf8+ Rxf8 40. gxf8=Q+ Kxf8 41. Kf1 Kf7 42. Ke2 Kf8 43. c4! bxc4 44. Kd2 Kg7 45. b5 Kf8 46. b6 Kf7 47. b7 Ke8 48. Kc3 Ke7 49. b8=Q h6 50. gxh6 Kf7 51. h7 g5 52. h8=Q Ke6 53. Qbxe5+ Kd7 1 : 0.

Literary Theory

Leela Chess Zero – AllieStein
Top Chess Engine Championship Season 17 — Division P; tcec-chess.com, April 7, 2020
Modern Defence A42

1. c4 g6 2. d4 Bg7 3. Nc3 d6 4. e4 Nc6 5. Be3 e5 6. d5 Nce7 7. g4 f5 8. gxf5 gxf5 9. Qh5+ Kf8 10. 0-0-0 f4 11. Bd2 Nf6 12. Qe2 Rg8 13. Bh3 b6 14. Kb1 h6 15. Bxc8 Qxc8 16. Be1 Nh7 17. h4 Bf6 18. f3 Rg6 19. Nh3 Kg8 20. Qf1 Qd7 21. Rd2 Kh8 22. Nf2 h5 23. Nb5 Kg7 24. Nh3 Kh6 25. Rdh2 Rg7 26. Bd2 Ng6 27. Nc3 Nhf8 28. Ne2 Kh7 29. Bc3 Qd8 30. Ng5+ Kh6 31. a3 Qe7 32. Nh3 Kh7 33. Ng5+ Kh6 34. Bd2 Re8 35. Ka2 a6 36. Nh3 Kh7 37. Ng5+ Kh6 38. Bc3 Rc8 39. Qc1 Rd8 40. Bd2 Rd7 41. Qf1 Rg8 42. Be1 a5 43. Qh3 Qe8 44. Qf5 Bd8 45. Bf2 Nh7? So as it went AllieStein came out quite badly from its neural wanderings, but its last move makes things irreversibly worse. Comparatively best was 45. ... Rdg7! and if 46. Qc8 then 46. ... Qd7 47. Qa6 Ne7 defending stubbornly. 46. Ne6 Ne7 47. Qh3 Ng6 48. Rg2 Rf7

49. Ng3! Also very strong was 49. Rg5!+− with the threat of 50. Rxh5+ Kxh5 51. Qg4+ Kh6 52. Qg5+ Nxg5 53. hxg5 mate. 49. ... fxg3 50. Qxg3 Rf4 51. Be3 Qf7 52. Nxf4 exf4 53. Bxf4+ Nxf4 54. Qxg8 Qf8

The time has come for Leela Chess Zero to take over the whole board: 55. Rg5! a4. The Rook is taboo due to mate in a few moves. 56. c5! bxc5 (56. ... dxc5 57. e5+−) 57. b3! The pointe. 57. ... axb3+ 58. Kxb3 Be7 59. a4 c6 60. dxc6 Qf6 61. Rhg1 Bf8 62. c7 c4+ 63. Ka2 c3 64. c8=Q c2 65. Qf5 c1=N+ 66. Rxc1 Nxg5 67. Qgxg5+ Qxg5 68. hxg5+ 1 : 0.

Life in the Desert

Stockfish – Stoofvlees

Top Chess Engine Championship Season 17 — Division P; tcec-chess.com, April 1, 2020

Spanish Game C88

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. 0-0 Be7 6. Re1 b5 7. Bb3 0-0 8. a4 Bb7 9. d3 d6 10. Nbd2 Na5 11. Ba2 c5 12. Nf1 bxa4 13. Bg5!?TN (13. Ne3 Bc6 14. Nh4 Bd7 15. Nhf5 Rb8 16. Qf3 Kh8 17. Qg3 Nh5 18. Qg4 g6 19. Qf3 Nc6 20. c3 Nf4 21. Nxe7 Qxe7 22. Nd5 Nxd5 23. Bxd5 f6 24. Qg3 Rb6 25. f4 exf4 26. Bxf4 Ne5 27. d4 g5 28. Bc1 cxd4 29. cxd4 Ng6 30. Qf2 Bc6 31. Be6 Rb4 32. Bf5 Nh4 33. d5 Bb5 34. Ra3 ½ : ½ Caruana – Tomashevsky, Grand Prix 2014–2015, 1st stage, Baku 2014) 13. ... Rb8 14. Bd2 Bc8 15. Ne3 Bd7 16. Bb1 h6 (16. ... Rxb2 17. Bxa5 Qxa5 18. Nc4±) 17. Bc3 Kh8 18. Nd2 Ng8 19. Nf3 Nb7 20. Bd2 Qc8 21. Ra3 Bd8 22. c3 Na5 23. Bc2 Nb3 24. Bxb3 axb3 25. Rxb3 a5 26. Rxb8 Qxb8 27. Qc2 Ne7 28. Rb1 Qa7 29. Ra1 f5 30. Be1 f4 31. Nc4 Bg4 32. Nfd2 f3 33. Qd1 Bh5 34. h3 Qd7 35. Ne3 Kh7 36. b3

36. ... c4!? (36. ... Ng6! 37. g4 Nf4 38. Qxf3 Rf6→) 37. Ndxc4 Rf4! 38. g3 Qxh3 (Δ ... Ne7-g6) 39. Bd2 Be8 40. Qf1 Qh5 41. gxf4 exf4 42. Nf5 Ng6. Also after 42. ... Nxf5 43. exf5 Qxf5 Black, despite being a Rook down, has at least a draw; for instance: 44. Kh2 Bd7! 45. Qh1 Qh5+ 46. Kg1 Qg6+ with perpetual check. 43. Ncxd6 Bd7 44. c4 Be7? Stoofvlees probably commits the last mistake. Instead 44. ... Bb6! 45. d4 Bxd4 46. Rxa5 Qg5+ 47. Kh2 Ne5!∞ would have compelled Stockfish to give back most of its wealth, with a likely draw by perpetual check in view. 45. c5+− Bh4 46. Ra2 a4 47. Bc3 axb3 48. Rb2 Ne7 49. Rxb3 Qg4+ 50. Kh1 Ba4 51. Rb7 Bc6 52. Rc7 Bg3 53. Bf6 Qh5+ 54. Bh4 Bd5 55. Rxe7 Bxh4 56. Qh3 Bf7 57. Rxf7 Kh8 58. Rxg7 Qxf5 59. Qxf5 Kxg7 60. Qf7+ Kh8 1 : 0. Because of 61. Qg6 ~ 62. Nf7 mate.

An employee rests inside a deserted office building in Belgrade, Serbia. Photo: Marko Đurića/Reuters.

Darwin Machines

Stockfish – Fire
Top Chess Engine Championship Season 17 — Division P; tcec-chess.com, March 22, 2020
Sicilian Defence B30

1. Nf3 Nf6 2. Nc3 c5 3. e4 Nc6 4. Bb5 g6 5. e5 Ng4 6. Bxc6 dxc6 7. h3 Nh6 8. d3 Bg7 9. Ne4 b6 10. a4!?TN a5 11. Ng3 Be6 12. Qe2 Bd5 13. 0-0 Bxf3. A very artificial pointe. 14. Qxf3 Qd5 15. Qe2! 0-0 16. Bf4 e6 17. Ne4 Nf5 18. g4 Nd4 19. Qd1 c4 (19. ... Bxe5?? 20. c4+−) 20. Re1 b5 21. Bg5 cxd3 22. Qxd3 Qc4 23. Qd1 bxa4. Not 23. ... Bxe5 on account of 24. Nd2 Qd5 25. c3 winning material. 24. Be7 Rfb8. Not an easy choice — or else, after 24. ... Rfe8 25. Bf6! White is going to dominate the dark squares.

25. Ra3! c5 26. Rc3 Qb5 27. Bxc5 Nc6 28. Nf6+ Kh8 29. Qf3 Rc8 30. h4! h6. If 30. ... Qxb2 then 31. h5! with the devastating threat of h5-h6. 31. g5! h5

32. Nxh5! Nxe5. 32. ... gxh5 33. Qxf7 gives White a winning attack. 33. Rxe5 Bxe5 34. Qe3! Bg7. Or 34. ... gxh5 35. Qxe5+ Kg8 36. g6! winning by force. 35. Nxg7 Kxg7 36. Qe5+ Kg8 37. h5 Rxc5 (37. ... gxh5 38. g6!+−) 38. Rxc5 Qb4 39. c4 a3 40. hxg6! Stockfish’s demonstration is as simple as powerful. 40. ... axb2 41. gxf7+ Kf8 42. Qh8+ Ke7 43. Rc7+ Kd6 44. Qxa8 Kxc7 45. f8=Q Qxf8 46. Qxf8 b1=Q+ 47. Kg2 Qe4+ 48. Qf3 Qg6 1 : 0.

Euclid’s Window

Stockfish – Houdini
Top Chess Engine Championship Season 17 — Division P; tcec-chess.com, March 20, 2020
Sicilian Defence B63

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6 6. Bg5 Qb6 7. Nb3 e6 8. Qd2 Be7 9. 0-0-0 0-0 10. Kb1 Rd8 11. Be2!? An interesting novelty, offering a Pawn sacrifice for a thematic Kingside attack. A relatively recent game continued: 11. h4 a6 12. g4 Qc7 13. Bxf6 Bxf6 14. g5 Bxc3 15. Qxc3 e5 16. h5 Qe7 17. h6 g6 18. f4 Bg4 19. Rd2 Be6 20. Rf2 Rac8 21. f5 gxf5 22. exf5 Nd4 23. Qe1 Nxc2 24. Rxc2 Bxf5 25. Nd4? (25. Na1) 25. ... Bg6 26. Bh3? Qc7!−+ Đukić – Kožul, Podgorica 2018, match game 3. 11. ... Qxf2. Maybe Black shouldn’t accept the challenge from such a calculating machine. 12. Rhf1 Qb6 13. Bxf6 gxf6. 13. ... Bxf6 14. Rxf6 gxf6 15. Qh6 implies similar consequences to those in the game. 14. Qh6 Ne5

15. Rd3! (Δ Rd3-h3) 15. ... Nxd3 16. Bxd3 (Δ Rf1-f3-g3+) 16. ... Bf8 17. Qxf6 Rd7 18. Rf4 (Δ Rf4-g4+) 18. ... h5 19. Qg5+ Bg7 20. Rf1 h4. 20. ... Qd8 21. Qxh5 looks no better. 21. g4! a5 22. a4 Qd8 23. Qh5 Be5 24. g5 Qf8

25. Rf6! Stockfish affords itself to sacrifice a second Exchange! 25. ... Rb8. Black can’t accept the gift with 25. ... Bxf6 due to 26. gxf6 followed by Qh5-g5+ and e4-e5 with mate on delivery. If, instead, 25. ... Qg7 then likewise 26. Rh6! with overwhelming effect. 26. Rh6! Stockfish concludes impressively. 26. ... b5 27. axb5 Qg7 28. g6 Re7 29. Nxa5 Bd7 30. Rh7 Qf6 31. g7 Qg6 32. Qxg6 fxg6 33. Rh8+ Kxg7 34. Rxb8 Bxh2 35. b6 d5 36. Rd8 Rf7 37. Be2 d4 38. Nd1 Bg3 39. Bg4 Bb5 40. Rxd4 Ba6 41. c4 Rf4 42. Bh3 g5 43. Bxe6 Rf6 44. Rd7+ Kh8 45. Re7 h3 46. Bxh3 Rxb6 47. Nc3 Bf2 48. Nd5 Rh6 49. Bf5 Be1 50. b4 Kg8 51. Re6 Rh1 1 : 0.

A lone guest talks on his mobile phone at a hotel in 香港 (Hong Kong), China. Photo: Tyrone Siu/Reuters.