Two Halves

Stockfish – Stoofvlees

Top Chess Engine Championship Season 20 — FRC3 Final League; tcec-chess.com, March 14, 2021

rqkbbnnr/pppppppp/8/8/8/8/PPPPPPPP/RQKBBNNR w HAha - 0 1

Position #697

1. d4 d5 2. c4 dxc4 3. Ne3 c5 4. dxc5 Nf6. Here the alternative was to maintain the symmetry with 4. ... Ne6 (5. Nf3 Nf6), but in any case the text, though not strictly symmetrical, is not too asymmetrical either. Black temporarily sacrifices a Pawn to keep development going. 5. Qc2 Ne6 6. Qxc4 Qe5 7. Bb4. Yet it is not too surprising that a machine wants to hold on to its material advantage. 7. ... a5 8. Ba3 Bc7 9. Nf3 Qh5. Also worth considering was 9. ... Qf4 followed by a-side castling (0-0-0) — whether before or after the exchange of Queens is irrelevant. 10. g4! Qh6

11. g5! Only thus. If, instead, 11. h4? then 11. ... Qf4! 12. Qxf4 Bxf4 13. Nd2 0-0-0! with powerful advantage. 11. ... Nxg5 12. Nf5 Qh3 13. Nxe7+ Kb8 14. c6! After 14. Nxg5 Qg2 Black wins back the Knight with good play for the Pawn. 14. ... Ra6. Not 14. ... b6?? because of 15. Nxg5 Qg2 16. Qb5! Qxh1 17. Bd6! winning immediately. 15. cxb7 Rb6 16. Nxg5 Qg2 17. Re1 Qxg5+ 18. e3

18. ... Bb5! Probably the only move. Black gives up a third Pawn in order to keep his chances of survival as high as possible. Incidentally, Black could not take on b7 either with the King or with the Rook on account of White’s Bishop going to f3. 19. Qxf7

19. ... Bd6? But Black eventually goes astray. 19. ... Rd8! was the consistent corollary of its previous move, since after 20. Bb3 (20. Bf3 should not worry Black too much after 20. ... Qh4) 20. ... Be2! 21. 0-0-0 Bxd1 22. Rxd1 Qb5!∞ it is anything but clear how White can make any progress. 20. Bxd6+ Rxd6 21. Bc2 Bd7? There’s something tremendously human about Black’s last error. ⌓ 21. ... Rd7! still gave some chances of putting up a defence. 22. h4 Qg2 23. Qc4 Re6 24. 0-0-0! A most powerful developing move! The rest is simply technique. 24. ... Qxb7 25. Rd3 Rb6 26. Red1 Re8 27. Nd5 Rc6 28. Qf4+ Ka8 29. Rb3 Nxd5 30. Rxb7 Nxf4 31. Rdxd7 Nd3+ 32. Kb1 Nc5 33. Ra7+ Kb8 34. Rxg7 Rd8 35. a3 Rd2 36. Rxa5 Rxf2 37. Rb5+ Ka8 38. Rg4 Rf1+ 39. Ka2 Rf7 40. Rc4 Rfc7 41. Bxh7 Rxh7 42. Rcxc5 Re6 43. Rc4 Ra6 44. Rcb4 Re7 45. h5 Rh7 46. e4 Rb7 47. Rxb7 Rxa3+ 48. Kb1 Ra1+ 49. Kc2 Rc1+ 50. Kd3 Rc3+ 51. Kd4 Rd3+ 52. Kc5 Rd5+ 53. Kb6 Rd6+ 54. Kb5 Rd1 55. Rb6 Rc1 56. Ra4# 1 : 0.

The Golden Fish

Stockfish – Stoofvlees

Top Chess Engine Championship Season 21 — Division P; tcec-chess.com, June 22, 2021

Sicilian Defence B81

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e6 6. g4 Be7 7. g5 Nfd7 8. h4 Nc6 9. Be3 0-0 10. f4 Qb6 11. a3!? Indirectly defending the b-Pawn. Instead, the human theory gave only 11. Rb1 d5 12. e5⩲ Kruppa – Golod, 57th Ukrainian Chess Championship, Kharkov 1988. 11. ... d5. Of course not 11. ... Qxb2?? because of 12. Na4 trapping the Queen. On the other hand, it would be disconcerting, to say the least, if the text move were the cause of Black’s calamities. And yet... 12. exd5 Nxd4 13. Bxd4 Bc5 14. Bxc5 Nxc5 15. Qd4 exd5. Again here, if 15. ... Qxb2? then 16. Qxc5! Qxa1+ 17. Kd2 with overwhelming compensation for the Exchange. Maybe 15. ... e5 could be considered, even if also in this case White would have little to worry about: 16. Qb4! exf4 17. 0-0-0 with powerful advantage. 16. 0-0-0 Bg4. If Stoofvlees were a human being rather than a machine, it could be inferred that “he” had relied a lot upon this move. 17. Nxd5 Qa5

18. h5! This gain of tempo proves devastating. 18. ... Ne6. The Rook is taboo, since 18. ... Bxd1? 19. h6! Ne6 20. Ne7+ Kh8 21. hxg7+ Nxg7 22. Qxd1 gives White a mating attack. 19. Qe5 Qc5 (19. ... Bxd1?? 20. Ne7++−) 20. b4 Qf2 21. Bd3 Rfd8. The Rook is untouchable for the same reason as mentioned above: 21. ... Bxd1? 22. Ne7+ Kh8 23. h6! with mating attack. 22. h6. Threat: Bd3xh7+. 22. ... g6. If 22. ... Rxd5!? (just hoping for 23. Qxd5?? Qxf4+ 24. Kb2 Bf3∞) then 23. Bxh7+! winning by force. 23. Ne7+ Kf8

24. Nxg6+! hxg6. If 24. ... fxg6 then 25. Qf6+ Kg8 (or 5. ... Ke8 26. Bb5+ followed by mate) 26. Bc4! with mate in a few moves. 25. h7 Ke7 26. Qf6+ Kd7 27. Qxf7+ Kc6 28. Be4+ Kb5 29. Qxb7+ Qb6

30. h8=Q! Bxd1. Or 30. ... Rxh8 31. Qd7+! followed by mate in two. 31. Qe5+ Nc5 32. Bc6+ Kc4 33. Qf7+ Ne6 34. Qfxe6+ Rd5 35. Q6xd5# 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.