Really serious endgame issues

[OliverBr]

Hi,

It's know since a long time that OliThink is weak in endgames (not using syzygy tablebases or neural net ist not an excuse for this bad play).
Now I have witnessed an horrible endgame where white looked much better. At some point (around 50) OliThink throws out a lot of "draw" evaluations while the opponent (Qapla! lol) improves its rating from move to move.

OliThink does not even have an special implementation for endgame, but it botches it almost always.
Who may help by example of this game?

[pgn][Site "118th Amateur D11"]
[Date "2025.06.12"]
[White "OliThink 5.11.4"]
[Black "Qapla 0.3.2"]
[Result "0-1"]

1. e4 {(Book)} e5 {(Book)} 2. Nc3 {(Book)} Nf6 {(Book)} 3. d3 {(Book)} Bc5 {(Book)} 4. Bg5 {(Book)} h6 {(Book)} 5. Bh4 {(Book)} g5 {(Book)} 6. Bg3 {(Book)} d6 {(Book)} 7. a3 {(Book)} a6 {(Book)} 8. Be2 {(Book)} Nc6 {(Book)} 9. Nf3 {(Nf3 O-O O-O Be6 Re1 Kh8 Nd2 Rg8 Nb3 Ba7 Bf3 Bd7 Qd2 Nd4 Nxd4 Bxd4 h3 Qe7 a4 Qe6 a5 Rae8) -0.32/25 17} Be6 {(Be6 O-O O-O h3 Qc8 Nd2 Nd4 Nb3 Nxb3 cxb3 c6 b4 Bd4 Rc1 Rd8 Bh5 b5 Re1 Nxh5 Qxh5) 0.39/19 30} 10. Nd2 {(Nd2 O-O Nb3 Ba7 O-O Kh7 Qd2 Rg8 Qc1 Bd7 h3 Rb8 Re1 Qe8 Qd2 Nd4 Nxd4 Bxd4 Kh1 Qe6 Bf3 g4 hxg4 Nxg4 Bxg4 Qxg4 a4) -0.36/27 33} Nd4 {(Nd4 Nb3 Nxb3 cxb3 c6 b4 Bd4 O-O O-O Rc1 b5 Qd2 Rc8 Bf3 Re8 Be2 Nd7 Kh1 a5 bxa5 Qxa5 Bf3) 0.44/20 18} 11. Nf3 {(Nf3 Nxe2 Qxe2 Nh5 O-O O-O Rad1 Ba7 Nd2 Nf4 Bxf4 gxf4 Qh5 Qg5 Qxg5+ hxg5 Nd5 Bxd5 exd5 f6 Nf3 c6) -0.50/24 41} Nxe2 {(Nxe2 Qxe2 b5 O-O Bb6 Rfd1 O-O Qd2 Kh7 d4 g4 dxe5 gxf3 exf6 fxg2 Nd5 Bxd5 exd5 Qxf6 Qd3+ Kg8 c3 Qg5) 0.43/19 18} 12. Qxe2 {(Qxe2 h5 h3 h4 Bh2 Nd7 Rd1 f6 d4 Bb6 O-O O-O Rfe1 Bf7 Nd5 Qe8 Nxb6 Nxb6 d5 Bg6 Qd2) -0.37/23 19} Nh5 {(Bb6 O-O-O g4 Nh4 Bd4 Qd2 c6 Nf5 Bxf5 exf5 Kd7 h3 Bxc3 Qxc3 gxh3 Rxh3 Nd5 Qb3 b5 Kb1) 0.39/18 31} 13. O-O {(O-O O-O Rfe1 f5 exf5 Bxf5 d4 exd4 Nxd4 Bxd4 Qc4+ Kh7 Qxd4 Bxc2 b4 Ng7 Nd5 Rf7 Ne3 Bg6 Qd5 b5 Qd4) -0.58/22 17} O-O {(O-O Nd2 Nf6 Kh1 b5 f3 Bb6 Rfe1 Nh5 Bf2 c5 Qe3 Rc8 Nb3 Qd7 a4 Bxb3 cxb3 Nf4 axb5 axb5) 0.51/20 18} 14. Rad1 {(Rad1 Ba7 Kh1 Kh8 Nd2 Nf4 Bxf4 gxf4 h3 f5 Rde1 Bd4 Qf3 c6 Nc4 Bxc4 dxc4 Qg5 exf5 Qxf5 Qe4) -0.58/24 61} Ba7 {(Ba7 Kh1 b5 Nd2 Nf6 f3 Kg7 Bf2 c5 g4 Bb6 h4 Rb8 h5 Re8 Rfe1 Rb7 Nb3 b4 axb4 Bxb3) 0.50/20 18} 15. Nd2 {(Nd2 Nf4 Bxf4 gxf4 h3 Qg5 Qf3 f6 Rfe1 Qg3 Rf1 c6 Kh1 Qxf3 Nxf3 Kf7 Nh4 Rg8 Nf5 Bxf5 exf5 Bd4 Ne4) -0.64/23 17} g4 {(g4 Nc4 Qg5 Ne3 Nxg3 hxg3 c6 Qd2 Rae8 Ne2 Bxe3 Qxe3 Qxe3 fxe3 b5 Nc3 f6 b3 Kh7 Rde1 a5 Kh2) 0.66/20 16} 16. Nc4 {(Nc4 Qg5 Ne3 Bd4 Qd2 Nf4 Kh1 Rab8 Bxf4 exf4 Ned5 Bxd5 Nxd5 Bxb2 Nxf4 Bxa3 Nd5 Qxd2 Rxd2 h5 Rb1 c6) -0.38/24 18} Qg5 {(Qg5 Ne3 c6 Qd2 Nxg3 hxg3 Rae8 Ne2 f5 Nxf5 Qxd2 Rxd2 Bxf5 exf5 Rxf5 c4 Ref8 Nc3 R5f7 Rc2 Bd4 Ne4 Rd7 Rfc1 d5) 0.53/21 19} 17. Ne3 {(Ne3 Bd4 Qd2 Kh7 Ncd5 Bxd5 Nxd5 Qxd2 Rxd2 Bxb2 Nxc7 Rac8 Nd5 Bxa3 Bh4 f6 Rb1 Rf7 c3 Bc5 Kh1) -0.34/23 17} Nxg3 {(Nxg3 hxg3 f6 Qd2 Rf7 Ne2 Bxe3 Qxe3 Qxe3 fxe3 Raf8 b3 f5 exf5 Rxf5 Rxf5 Bxf5 e4 Bd7 Nc3 h5 Rf1 Rxf1+ Kxf1 Kg7) 0.73/22 19} 18. hxg3 {(hxg3 f6 Rde1 Qh5 Qd2 Rf7 Ne2 Rb8 Qc3 Kh7 d4 Bb6 Nc4 exd4 Qd3 Bxc4 Qxc4 d3 cxd3 c6) -0.50/24 25} f6 {(f6 Qd2 Rf7 Ne2 Bxe3 Qxe3 Qxe3 fxe3 Raf8 Nc3 f5 exf5 Bxf5 e4 Be6 Rxf7 Rxf7 Rf1 c6 b3 b5 Rf2 a5) 0.80/22 19} 19. Qd2 {(Qd2 Rf7 Ne2 h5 d4 Re8 c3 h4 f4 gxf3 Rxf3 Kf8 gxh4 Qxh4 Ng3 exd4 cxd4 Rh7 Qf2 Kg8 Rxf6 Kh8) -0.55/24 29} Rf7 {(Rf7 Ne2 Bxe3 Qxe3 Qxe3 fxe3 Raf8 d4 f5 dxe5 dxe5 exf5 Rxf5 Rxf5 Rxf5 b3 Kg7 c4 Rf8 Nc3 Kg6 Nd5 Bxd5) 0.76/22 18} 20. Ne2 {(Ne2 Re8 Rfe1 h5 c4 Ref8 d4 f5 Nxf5 Qxd2 Rxd2 Bxf5 exf5 Rxf5 Rf1 Kg7 Rd3 Kg6 b3 Bxd4 Nxd4 exd4 Rxd4 Re5) -0.72/25 20} Bxe3 {(Bxe3 Qxe3 Qxe3 fxe3 Raf8 b3 Kg7 c4 f5 exf5 Bxf5 Nc3 Bg6 Rxf7+ Rxf7 Rd2 c6 d4 b5 dxe5 dxe5 e4 h5 cxb5 axb5) 0.75/22 18} 21. Qxe3 {(Qxe3 h5 Nc3 h4 gxh4 Qxh4 Qg3 Qxg3 fxg3 Kg7 d4 Raf8 Nd5 Bxd5 exd5 f5 dxe5 dxe5 Kf2 f4 Rfe1 fxg3+ Kxg3 Rf2 d6 cxd6) -0.46/28 20} Qxe3 {(Qxe3 fxe3 Raf8 b3 f5 exf5 Rxf5 Rxf5 Bxf5 e4 Bg6 Nc3 Kg7 a4 c6 a5 Rf6 Rf1 Rxf1+ Kxf1 Bf7 Kf2 Kf6 b4 h5) 0.74/24 21} 22. fxe3 {(fxe3 Raf8 c4 f5 Nc3 fxe4 Rxf7 Kxf7 Rf1+ Ke7 Rxf8 Kxf8 Nxe4 Bf5 Kf2 Ke7 Ke2 Bxe4 dxe4 Ke6 b4 h5 Kd3 b6 a4 a5 b5 Kf6 Kc3) -0.30/29 14} f5 {(f5 exf5 Rxf5 Rxf5 Bxf5 c4 Kg7 Nc3 Rf8 a4 c6 Rd2 b6 b3 Bg6 e4 h5 b4 Rf6 b5 cxb5 axb5 a5 Rf2 Rxf2) 0.75/23 19} 23. exf5 {(exf5 Bxf5 e4 Bg6 Nc3 c6 Rf2 Rxf2 Kxf2 Rf8+ Ke3 Rf6 d4 exd4+ Rxd4 Kf8 Ne2 Ke7 Rb4 b5 Nf4 h5 Rd4 Bf7 b3 Ke8 a4 Ke7 a5 Kd7) -0.27/31 15} Bxf5 {(Bxf5 c4 Bg6 e4 c6 Nc3 h5 b3 Rxf1+ Kxf1 Rf8+ Ke2 Kg7 Rc1 Bf7 b4 Be6 a4 Kg6 a5 Kg5 Rb1 Rf7 Rh1 Rf8) 0.77/24 19} 24. e4 {(e4 Bg6 Nc3 c6 d4 Rxf1+ Kxf1 Rf8+ Ke2 exd4 Rxd4 Rf6 Ke3 b5 Ne2 Kf7 Nf4 Ke7 Nd3 a5 Nf4 Bf7 b3 h5 a4 b4 Rd1 Rh6 Rd4 h4 gxh4) -0.22/29 19} Be6 {(Be6 Rxf7 Kxf7 Kf2 Ke7 Ke3 Rh8 b3 h5 d4 exd4+ Nxd4 Kd7 c4 b5 cxb5 axb5 Rd3 c6 Rc3 Rc8 a4 bxa4 bxa4) 0.68/23 32} 25. Rxf7 {(Rxf7 Bxf7 Kf2 Rf8 Ke3 h5 d4 Re8 d5 Rf8 c4 Be8 b3 Kh7 Nc3 Kg6 Kd3 Rf2 Rd2 Rxd2+ Kxd2 Kf6 Kd3 c5 Nd1 Bd7 Ne3 b6 Kc3 a5 Kd3) -0.05/32 17} Bxf7 {(Bxf7 Kf2 h5 Ke3 b5 d4 exd4+ Nxd4 Re8 Nf5 Kh7 Kf4 Kg6 b3 Rf8 Nh4+ Kf6 Nf5 a5 Nd4 Kg6 b4 Ba2+ Nf5 Be6) 0.74/22 17} 26. Kf2 {(Kf2 h5 Nc3 Rf8 Ke3 Kg7 Nd5 Bxd5 exd5 a5 d4 Re8 Rd2 b5 Rf2 Kg6 c3 exd4+ Kxd4 a4 Kd3 Re5 Kd4 Re8) 0.00/28 19} h5 {(h5 Ke3 Kg7 b3 b5 d4 exd4+ Nxd4 Re8 Rf1 Bd5 Rf4 Kg6 b4 Be6 Nxe6 Rxe6 Rf5 Re8 Kf4 Rd8 e5 dxe5+ Rxe5 Rf8+) 0.73/23 25} 27. Ke3 {(Ke3 Kg7 Nc3 Rf8 Nd5 c6 Nb6 Be6 b3 Kg6 d4 Kf6 dxe5+ Kxe5 Rh1 Rh8 c4 Rh6 b4 Kf6 c5 dxc5 bxc5 Kg5 Rf1 Rf6 Rf4) 0.00/30 14} b5 {(b5 d4 exd4+ Nxd4 Re8 Ne2 Kg7 Nf4 Kh7 b3 Bg6 Rd4 Kh6 b4 Bf7 Nd5 Rc8 Rd1 Kg5 Rd3 Bg6 Nf4 Rf8) 0.80/23 27} 28. Nc3 {(Nc3 Kf8 Nd5 c6 Nb6 Rd8 Rf1 Ke7 a4 d5 exd5 cxd5 d4 e4 Rf5 Kf8 a5 Kg7 c3 Rd6 Rg5+ Kf6 Re5 Kg6 b3 Be6) -0.10/30 29} Kf8 {(Kf8 d4 exd4+ Rxd4 Ke7 Nd5+ Kd7 Rd1 Rc8 b4 Rf8 Nf4 Rh8 Rf1 c6 Kd4 Ke7 Nd3 Bc4 Ke3 Rh6 Kd4 Rf6 Rh1 Bxd3) 0.72/23 26} 29. Rf1 {(Rf1 c6 a4 Ke7 a5 Rf8 Nd1 Bg6 Rxf8 Kxf8 c3 Ke7 Kd2 Kf7 b4 Ke6 Ke3 Kf6 c4 Bf7 cxb5 cxb5 Nc3 Be6) -0.29/28 25} c6 {(c6 Nd1 Kg7 Kd2 Kg6 Ne3 Be6 c4 a5 cxb5 cxb5 Nf5 Bxf5 Rxf5 Rc8 Rf1 a4 Ke3 Re8 d4 exd4+ Kxd4 Re5 Rf2 Rc5) 0.74/24 17} 30. Ne2 {(Ne2 Re8 d4 Kg7 dxe5 Rxe5 Rd1 d5 Nc3 Re6 Kf4 dxe4 Nxe4 Bg6 Rd4 a5 b3 Re7 c4 Bxe4 Rxe4 Rxe4+ Kxe4 Kf6 c5 a4 bxa4 bxa4) -0.25/28 17} c5 {(c5 Kd2 Kg7 b3 Kg6 Nc3 Be6 Nd1 Rd8 Ne3 a5 a4 bxa4 bxa4 Bd7 Nf5 Bxf5 Rxf5 Rb8 Rf1 Rb7 Ke3 Kg5) 0.75/23 16} 31. Nc3 {(Nc3 Ke7 Rf5 Rh8 b4 Rc8 Kd2 c4 Nd5+ Bxd5 exd5 cxd3 cxd3 Rf8 Rxh5 Rf2+ Ke3 Rxg2 Rh7+ Kf6 Rd7 Kf5 Rf7+ Kg5 Rg7+ Kh5 Ke4 Rxg3 Rh7+ Kg5 Rg7+ Kh5) 0.00/33 20} Kg7 {(Kg7 Kd2 Be6 b3 Kg6 Nd1 Rb8 Ne3 a5 Nf5 Bxf5 Rxf5 Re8 Rf1 b4 a4 Ra8 c4 Rc8 Ke3 Rb8 Kd2 Re8 Rf5 Ra8) 0.78/26 18} 32. b3 {(b3 Rc8 a4 b4 Nd5 Bxd5 exd5 a5 Ke4 Kg6 Rf5 Ra8 Rf2 Rb8 Rf5 Ra8) 0.00/36 12} Kg6 {(Kg6 Kd2 Be6 Nd1 Rb8 Ne3 a5 Nf5 Bxf5 Rxf5 Rc8 Ke3 b4 a4 Re8 Rf1 Ra8 Kd2 Rc8 c3 Rh8 Rf5 Ra8 Rf1 Rb8) 0.77/26 17} 33. a4 {(a4 b4 Nd5 Bxd5 exd5 a5 Ke4 Rb8 Rf5 Rc8 Rf2 Ra8 Ke3 Rb8 Ke4 Kg7 Rf5 Kg6 Rf2) 0.00/39 13} b4 {(b4 Nd1 Be6 Kd2 Kg5 Ne3 Rc8 c4 Re8 Ke2 Rc8 Kd2 Kg6 Nf5 Rd8 Ke3 Rd7 Rf2 Kg5 Ke2 Bxf5 Rxf5+ Kg6 Ke3 a5) 0.69/25 15} 34. Nd5 {(Nd5 Bxd5 exd5 a5 Ke4 Rb8 Ke3 Ra8) 0.00/49 12} Bxd5 {(Bxd5 exd5 Rh8 Ke4 a5 Ke3 Rg8 Ke4 Re8 Ke3 Rh8 Kd2 Rb8 c4 Rh8 Ke3 Ra8 Rf2 Rb8 Rf1 Rg8 Ke4 Rc8 Ke3 Rc7) 0.85/27 14} 35. exd5 {(exd5 a5 Rf2 Rb8 Rf1 Kg7 Rf5 Kg6 Ke4 Rc8 Rf2 Rb8 Rf1 Rc8 Rf5 Rb8 Rf1) 0.00/53 12} Rb8 {(Rb8 Ke2 Kg7 Kd2 Rg8 Ke2 Kg6 Ra1 Re8 Re1 Ra8 Rf1 Rc8 Ke3 Rg8 Rf2 Re8 Rf1 Rc8 Ke2 Rh8 Kd2 a5 Rf2 Rc8) 1.02/28 18} 36. a5 {(a5 Ra8 Ke4 Rb8 Ke3) 0.00/42 12} Rd8 {(Rd8 Rf2 Ra8 Rf1 Rb8 Rf2 Kg7 Rf5 Rh8 Ke2 Kg6 Rf1 Rd8 Kd2 Re8 Ke3 Ra8 Ke2 Rh8 Kd2 Rc8 Ke3 Re8 Kd2 Rg8) 0.80/28 38} 37. Ke4 {(Ke4 Rb8 Ke3) 0.00/59 20} Ra8 {(Ra8 Rf2 Rb8 Rf1 Rb5 Ra1 Kf6 Rf1+ Kg5 Ra1 Kg6 Ke3 Kh6 Rf1 Kg5 Ra1 h4 gxh4+ Kxh4 Kf2 Kh5 Ke3 Kg6 Ke4 Rb8) 0.45/29 14} 38. Ke3 {(Ke3 Rd8) 0.00/56 18} Re8 {(Re8 Rf2 Rg8 Ke2 Rh8 Ke3 Re8 Rf1 Rb8 Rf2 Rb5 Rf8 Rxa5 Rd8 Ra2 Rxd6+ Kf7 Kd2 Ra1 Rh6 Rg1 Rxh5 Rxg2+ Kd1 Kf6) 0.49/29 14} 39. Kd2 {(Kd2 e4 Re1 Kf5 Rf1+ Kg6) 0.00/42 16} Rg8 {(Rg8 Ke2 Kg7 Ke3 Rh8 Kd2 Kg6 Ke3 Ra8 Ke2 Rg8 Kd1 Rb8 Ke2 Rb5 Rf8 Rxa5 Rd8 Ra2 Rxd6+ Kf7 Kd2 Ra1 Rh6 Rg1) 0.36/28 13} 40. Ke3 {(Ke3 Rb8 Rf2 Re8 Ke4 Rb8 Rf1 Ra8) 0.00/49 16} Rc8 {(Rc8 Ke4 Rh8 Ke3 Ra8 Ke2 Rc8 Ke3 Rb8 Ke2 Rd8 Ke3 Kg7 Rf2 Rh8 Rf5 Rh6 Ke2 Rh7 Ke3 Rh8 Rf2 Re8 Rf5 Kg6) 0.09/30 15} 41. Rf2 {(Rf2 Rb8 Rf1) 0.00/55 24} Re8 {(Re8 Rf1 Ra8 Ke4 Kg7 Rf5 Rh8 Ke3 Kg6 Rf1 Rg8 Rf2 Kg7 Ke4 Rh8 Rf5 Kg6 Rf2 Rb8 Ke3 Kg7 Ke4 Rc8 Ke3 Rd8) 0.01/30 15} 42. Rf1 {(Rf1 Rc8) 0.00/54 11} Rh8 {(Rh8 Ke4 Kg7 Ke3 Rc8 Rf5 Kg6 Rf2) 0.01/30 14} 43. Rf2 {(Rf2 Re8) 0.00/50 22} Rc8 {(Rc8 Rf1 Rb8 Rf2 Rh8 Rf1 Kg7 Rf5 Rh7 Rf1 Rh6 Rf5 Rh8 Rf1 Re8 Ke4 Rb8 Rf2 Rh8 Rf5 Kg6 Rf1 Re8 Ke3) 0.01/31 16} 44. Rf1 {(Rf1 Re8) 0.00/55 13} Rb8 {(Rb8 Rf2 Rh8 Rf1 Kg7 Rf5 Rh7 Rf1 Rh6 Rf5 Rh8 Ke4 Kg6 Rf1 Rg8 Ke3) 0.01/31 14} 45. Rf2 {(Rf2 Rc8) 0.00/44 15} Kg7 {(Kg7 Ke4 Rd8 Ke3 Kg6 Ke4 Rh8 Ke3) 0.01/30 17} 46. Rf5 {(Rf5 Kg6 Rf2) 0.00/48 12} Rh8 {(Rh8 Ke4 Kg6 Rf2 Rg8 Ke3 Rb8 Rf1) 0.01/30 14} 47. Ke4 {(Ke4 Kg6 Rf2 Re8 Rf1 Ra8) 0.00/47 11} Kg6 {(Kg6 Rf1 Rg8 Ke3) 0.01/30 14} 48. Rf1 {(Rf1 Ra8) -0.13/53 47} Rd8 {(Rd8 Rf2 Rg8 Ke3 Rb8 Rf1) 0.01/32 14} 49. Rf2 {(Rf2 Re8 Rf1 Rh8 Rf2 Kg7 Ke3 Kg6 Ke4) 0.00/46 9} Rg8 {(Rg8 Rf1 Kg7 Ke3 Rb8 Rf5) 0.01/31 14} 50. Rf1 {(Rf1 Ra8) 0.00/56 28} Rh8 {(Rh8 Rf2 Rg8) 0.01/31 14} 51. Rf5 {(Rf5 Kg7 Ke3 Kg6 Rf2) 0.00/45 15} Rb8 {(Rb8 Rf1 Rb5 Ra1 Kg5 Ke3 Kf6 Rf1+ Kg7 Ke4 Rxa5 Kf5 Ra2 Rc1 Kf7 Kg5 a5 Kxh5 a4 bxa4 Rxa4 Kxg4 Kg6 Kf3 Ra2) 0.44/30 12} 52. Rf1 {(Rf1 Rh8) 0.00/45 17} Rb5 {(Rb5 Rf8) 0.00/31 47} 53. Rf8 {(Rf8 Rxa5 Rd8 Ra2 Rxd6+ Kf7 Kxe5 Rxc2 Rf6+ Ke8 Rxa6 Rxg2 Ke6 Re2+ Kd6 Re3 Kc7 Rxd3 d6 h4 Ra8+ Kf7 d7 hxg3 d8=Q Rxd8 Rxd8 g2 Rd1 Ke6) 0.72/26 9} Rxa5 {(Rxa5 Rd8 Ra2 Rxd6+ Kf7 Kxe5 Rxc2 Rd7+ Kg6 d6 Re2+ Kf4 Rxg2 Rc7 Kf6 Rh7 Ke6 d7 Rf2+ Ke4 Rf8 Rxh5 Kxd7 Rxc5 Rf3) 0.00/27 16} 54. Rd8 {(Rd8 Ra2 Rxd6+ Kf7 Rh6 Rxc2 d6 Rxg2 d7 Ke7 Rh7+ Kd8 Kd5 Rxg3 Ke6 Kc7 Rh8 Rxd3 Rc8+ Kb6 d8=Q+ Rxd8 Rxd8 g3 Kxe5 h4 Rg8 c4 bxc4 Kc5 Rc8+ Kb6 c5+ Kb7 Rg8 b3 Rd8 b2) 0.86/30 16} Ra2 {(Ra2 Rxd6+) 0.00/27 19} 55. Rxd6+ {(Rxd6+ Kf7 Rh6 Rxc2 d6 Rxg2 d7 Ke7 Rh7+ Kd8 Kd5 Kc7 Ke6 Rxg3 Rh8 Rxd3 Rc8+ Kb7 d8=Q Rxd8 Rxd8 g3 Kd5 h4 Rg8 e4 Kxe4 c4 Rg7+ Kc6 bxc4 b3 Rg6+ Kb7 c5 b2) 0.73/25 17} Kf7 {(Kf7 Kxe5) -0.60/27 77} 56. Rd7+ {(Rd7+ Kf6 Rh7 Rxc2 d6 Re2+ Kd5 Rd2 d7 Rxd3+ Kc6 c4 Rh8 cxb3 d8=Q+ Rxd8 Rxd8 e4 Rd2 Ke5 Kc5 e3 Re2 Ke4 Kc4 a5 Rb2 Kf5 Kxb3 Ke4 Ra2 Kd3 Rxa5) 1.50/26 16} Kf6 {(Kf6 Rh7 Rxc2 d6 Re2+ Kd5 Rd2 Rxh5 Rxd3+ Kc6 c4 bxc4 b3 Rh1 Ke6 Rh6+ Kf5 d7 b2 Rh5+ Ke6 Rh6+ Ke7 Rh7+ Kd8) 0.00/26 11} 57. Rh7 {(Rh7 Rxc2 d6 Re2+ Kd5 Rd2 d7 Rxd3+ Kc6 c4 Rh8 cxb3 d8=Q+ Rxd8 Rxd8 e4 Rd6+ Ke5 Rd5+ Kf6 Rxh5 e3 Kc5 a5 Rh1 Ke5 Rb1 Ke4 Rb2 Kd3 Rxb3+ Ke4 Kc6) 1.17/26 15} Rxc2 {(Rxc2 d6 Re2+ Kd5 Rd2 Rh6+ Kg5 Rh8 Rxd3+ Kc6 c4 bxc4 b3 d7 b2 Rb8 Kf6 c5 Ke7 Re8+ Kf6 Rb8) 0.00/26 16} 58. d6 {(d6 Re2+ Kd5 Rd2 Rh6+ Kg7 Rxh5 Rxd3+ Kc6 c4 bxc4 b3 Rxe5 Kf7 d7 b2 Rd5 Rxd5 cxd5 b1=Q d8=Q Qb5+ Kd6 Qb4+ Kc7 Qc5+ Kb7 a5 Qc7+ Qxc7+ Kxc7 a4 d6 a3 d7 a2) 1.32/28 8} Re2+ {(Re2+ Kd5 Rd2 Rxh5 Rxd3+ Kc6 c4 bxc4 b3 Rh6+ Kf5 Rh8 a5 d7 b2 Rb8 Ke6 Re8+ Kf5 Rb8) 0.00/26 9} 59. Kd5 {(Kd5 Re3 Rh6+ Kg7 Rxh5 Rxd3+ Kc6 c4 bxc4 b3 Rxe5 Kf7 d7 b2 Rd5 Rxd5 cxd5 b1=Q d8=Q Qc2+ Kd6 Qg6+ Kc5 Qc2+ Kb6 Qb2+ Kxa6 Qxg2 Qc7+ Kg8 Qc8+ Kf7 Qe6+ Kf8 d6 Qc6+ Ka7 Qc5+ Ka8) 1.47/27 13} Rd2 {(Rd2 Rh8 Rxd3+ Kc6 c4 d7 cxb3 d8=Q+ Rxd8 Rxd8 e4 Rd6+ Kf5 Rd5+ Ke6 Kc5 b2 Rd1 a5 Rb1 e3 Rxb2 Ke5 Re2 Ke4) -0.46/25 19} 60. Rh6+ {(Rh6+ Kg7 Rxh5 Rxd3+ Kc6 c4 bxc4 b3 Rxe5 b2 Re7+ Kf6 Re1 a5 Rb1 Rd2 d7 Ke7 Re1+ Kf7 Kc7 Rxd7+ Kxd7 a4 c5 a3 c6 a2 c7 a1=Q Rxa1) 1.01/24 10} Kf7 {(Kf7 Kc6 Rxd3 d7 Ke7 Rh7+ Ke6 Kc7 e4 d8=Q Rxd8 Kxd8 Ke5 Rxh5+ Kd4 Rh6 c4 bxc4 a5 Ra6 b3 Rxa5 e3 Ra1 Kxc4) -0.77/24 11} 61. Rxh5 {(Rxh5 Rxd3+ Kc6 c4 bxc4 b3 Rxe5 Rd4 c5 a5 Re1 a4 Kd7 b2 c6 a3 c7 Rc4 c8=Q Rxc8 Kxc8 a2 d7 b1=Q Rxb1 axb1=Q d8=Q) 0.93/24 9} Rxd3+ {(Rxd3+ Kxc5 Kf6 Rh6+ Kf7 Rh7+ Kf6 Rh8 Ke6 Rh6+ Kf7) 0.00/24 10} 62. Kc6 {(Kc6 c4 bxc4 b3 Rxe5 Rd2 Rf5+ Ke8 Kc7 b2 Rd5 Rxd5 cxd5 b1=Q d7+ Kf7 d8=Q Qc2+ Kb6 Qb3+ Kc6 Qc2+ Kb7 Qxg2 Qd7+ Kf6 Qd6+ Kg7 Qe5+ Kg6 Kxa6 Qa2+ Kb5 Qb3+ Kc6 Qc2+ Kd6 Kf7) 1.33/24 9} Rxb3 {(Rxb3) 0.15/25 11} 63. Rh7+ {(Rh7+ Kg6 Rb7 Rxg3 d7 Rd3 Kc7 Kf6 d8=Q+ Rxd8 Kxd8 e4 Rc7 e3 Re7 b3 Rxe3 c4 Re1 b2 Rf1+ Ke5 Ke7 Kd4 Ke8 Kc3 Rd1) 0.63/26 16} Kg6 {(Kg6 Ra7 Kf6 Rxa6 c4 d7 Rd3 Kc5+ Ke7 Kxb4 c3 Rc6 Rxg3 Rxc3 Rxg2 Rd3 Kd8 Kc4 e4 Rc3 Kxd7 Kd4 Rg1 Kxe4 Ke6) 1.61/23 9} 64. d7 {(d7 Rd3 Re7 b3 Re6+ Kf5 Rd6 Rxd6+ Kxd6 b2 d8=Q b1=Q Qc8+ Ke4 Qxg4+ Kd3 Qf3+ Kd2 Qf2+ Kd3 Qf3+) 0.00/28 9} Rd3 {(Rd3 Re7 Kf5 Rf7+ Ke4 Kxc5 b3 Kc6 b2 Rf1 Rc3+ Kb7 Rc1 Rxc1 bxc1=Q d8=Q Qc4 Qf6 a5 Qg6+ Kd4 Qxg4+ e4 Qd1+ Kc5) 2.65/23 12} 65. Re7 {(Re7 Kf5 Rf7+ Ke4 Rg7 b3 Rg8 c4 Rxg4+ Kf5 Rxc4 Ke6 Rb4 Rc3+ Kb6 Kxd7 g4 Rg3 Kxa6 Kc6 Rb5 e4 Rb6+ Kc5 Rb5+ Kc4 Ka5 Rxg2 Rb4+ Kd5 Rxb3) -1.35/29 32} Kf5 {(Kf5 Rf7+ Ke4 Kxc5 b3 Kc6 b2 Rf1 Rc3+ Kb7 Rc1 Rxc1 bxc1=Q d8=Q Qc4 Qg5 Kd3 Qf6 e4 Qf1+ Kc3 Qc1+ Kd4 Qf4 a5) 2.73/23 10} 66. Rf7+ {(Rf7+ Ke4 Rg7 b3 Rg8 c4 Rxg4+ Kf5 Rxc4 a5 Rc5 Ke6 Rxa5 Rxd7 Rb5 Rd3 g4 Rc3+ Kb7 e4 Rb4 e3 g5 Kd5 g6 e2 g7 e1=Q) -1.56/26 11} Ke4 {(Ke4 Kxc5 b3 Kc6 b2 Rf1 Rc3+ Kb7 Rc1 Rxc1 bxc1=Q d8=Q Qc4 Qg5 Kd3 Qf6 e4 Qf1+ Kc3 Qc1+ Kd4 Qd1+ Qd3 Qxg4 Kc3) 2.80/24 12} 67. Kxc5 {(Kxc5 b3 Kc6 b2 Rf1 Rc3+ Kb7 Rc1 Rxc1 bxc1=Q d8=Q Qb2+ Kxa6 Qa3+ Kb7 Qxg3 Qf6 Ke3 Kc8 Qf4 Qb6+ Ke2 Kb7 Qd4 Qc6 e4 Qb6 Qe5) -1.53/25 7} b3 {(b3 Kc6 b2 Rf1 Rc3+ Kb7 Rc1 Rxc1 bxc1=Q d8=Q Qc4 Qg5 Kd3 Qf6 e4 Qf1+ Kc3 Qc1+ Kd4 Qf4 a5 Kb6 Qb4+ Kc6 Qc5+) 2.73/23 12} 68. Kc6 {(Kc6 b2 Rf1 Rc3+ Kb7 Rc1 Rxc1 bxc1=Q d8=Q Qb2+ Kxa6 Qa3+ Kb7 Qxg3 Qf6 Ke3 Ka6 Qf4 Qb6+ Qd4 Qf6 Qc4+ Kb6 Qf4 Qd6 Qd4+ Kc6 Kf4) -1.52/26 8} b2 {(b2 Rf1 Rc3+ Kb7 Rc1 Rxc1 bxc1=Q d8=Q Qc4 Qg5 Kd3 Qf6 e4 Qf1+ Kc3 Qc1+ Kd4 Qf4 a5 Qxg4 Qb3+ Kc7 a4 Qf4 Qc3+) 2.95/24 14} 69. Rf1 {(Rf1 Rc3+ Kb7 Rc1 Rxc1 bxc1=Q d8=Q Qc4 Qg5 Qb3+ Kxa6 Qxg3 Qc1 Qd3+ Kb7 Qd5+ Kc7 Kf5 Qf1+ Kg6 Qa6+ Kg5 Qe2 Qd4 g3 Qc5+ Kd7 Qd5+ Kc7 Kh5 Qf2) -1.60/25 32} Rc3+ {(Rc3+ Kb7 Rc1 Rxc1 bxc1=Q d8=Q Qc4 Qg5 Kd3 Qf6 a5 Qf1+ Kd4 Qf2+ Kd5 Qd2+ Kc5 Qe3+ Qd4 Qc1+ Kb4 Qe1+ Kc4 Qc1+ Qc3) 2.82/24 12} 70. Kb7 {(Kb7 Rc1 Rxc1 bxc1=Q d8=Q Qc4 Qg5 Qb3+ Kxa6 Qxg3 Qc1 Qd3+ Kb7 Kf5 Qc5 Ke6 Qf8 Qd7+ Ka8 Qc6+ Ka7 Qd6 Qg8+ Kf5 Qf7+ Ke4 Qf1 Qc5+ Ka6 Qb4 Ka7 Kd5 Qc1) -1.66/25 10} Rc1 {(Rc1 Rxc1 bxc1=Q d8=Q Qc4 Qg5 Kd3 Qf6 e4 Qf1+ Kc3 Qc1+ Kd4 Qf4 a5 Qf6+ Kd3 Qf1+ Kc3 Qc1+ Kd4 Qd2+ Kc5 Qf2+ Kb4) 2.97/22 10} 71. Rxc1 {(Rxc1 bxc1=Q d8=Q Qc4 Qg5 Qb3+ Kxa6 Qxg3 Qc1 Qd3+ Kb7 Kf5 Qc5 Ke6 Qc6+ Qd6 Qc1 Qd5+ Kb6 Kf5 Qf1+ Kg5 Qe2 g3 Qe3+ Kh4) -1.63/23 30} bxc1=Q {(bxc1=Q d8=Q Qc4 Qg5 Kd3 Qf6 a5 Qf1+ Kd4 Qf2+ Kd5 Qf7+ Kc5 Qf2+ Qd4 Qf8+ Kb5 Qf1+ Qc4 Qb1+ Qb4 Qf5 Kc5+ Kc7 Qd4) 2.82/24 25} 72. d8=Q {(d8=Q Qb1+ Ka7 Qd3 Qc7 Qxg3 Qc4+ Ke3 Kxa6 Qf4 Qa2 e4 Kb6 Qf6+ Kb5 Qd6 Qf7 g3 Qc4 Qd7+ Kb4 Qd2+ Kc5 Qxg2) -1.88/21 6} Qb1+ {(Qb1+ Ka8 Qd3 Qf6 a5 Qg6+ Ke3 Qg5+ Kf2 Qxe5 Qxg3 Qxa5 Kxg2 Kb7 Qf3+ Kc8 Qc6+ Kb8 Qd6+ Ka8 g3 Qc7 Qd5+ Ka7 Qd4+) 3.14/22 9} 73. Ka7 {(Ka7 Qd3 Qb6 Qxg3 Kxa6 Qd3+ Kb7 Kf5 Qf2+ Kg5 Qb6 Qd5+ Kb8 e4 Qe3+ Kf5 Qf2+ Ke6 Qe3 Qe5+ Kb7 Ke7 g3 Qb5+ Ka7 Qa4+ Kb8 Ke6) -1.82/19 7} Qd3 {(Qd3 Qc7 Qxg3 Qc2+ Qd3 Qc6+ Qd5 Qc1 a5 Qg5 Qd7+ Kb6 a4 Qg6+ Kd4 Qc2 Ke3 Qc3+ Ke4 Qe1+ Kf5 Qf2+ Kg6 Qc2+ Kg5) 3.32/20 11} 74. Qa5 {(Qa5 Qxg3 Qxa6 Ke3 Qf1 Qf2 Qc4 Qf4 Qa2 Qd4+ Ka6 g3 Kb7 Qd7+ Kb6 Qd6+ Kb7 e4 Qb3+ Qd3 Qe6 Qb5+ Kc8 Qc5+ Kb7 Qb4+ Ka7 Qd4+ Qb6) -2.01/21 10} Qxg3 {(Qxg3 Qb4+ Ke3 Kxa6 Kf2 Qd2+ Kf1 Qd5 Qxg2 Qd1+ Kf2 Qd2+ Kg1 Qe3+ Qf2 Qxe5 g3 Ka5 g2 Qa1+ Kh2 Qh8+ Kg3 Qc3+ Qf3) 3.55/19 9} 75. Qa4+ {(Qa4+ Ke3 Kxa6 Qf4 Qa2 Qd4 Kb5 Ke4 Kc6 Kf4 Qb3 e4 g3+ Kf5 Qb5+ Qe5 Qf1+ Kg5 Qb5 Qxb5+ Kxb5 e3) -2.06/19 6} Ke3 {(Ke3 Kxa6 Kf2 Qc2+ Kg1 Qe4 Qxg2 Qxe5 g3 Qc3 Qa8+ Kb6 Qb8+ Ka5 Qa7+ Kb4 Qb7+ Ka3 Qe7+ Kb3 Qe6+ Kc2 Qe2+ Kb1 g2) 3.87/21 12} 76. Kxa6 {(Kxa6 Kf2 Qc2+ Kg1 Qe2 Qxg2 Qxe5 g3 Kb6 Qf2+ Kc7 Qc2+ Kb6 Qd3 Qe1+ Kg2 Qe5 Kf1 Qf6+ Kg1 Qa1+ Qf1 Qe5 g2 Ka5 Qf2 Qa1+ Kh2 Qe5+ Kh3 Qe6+ Kg3 Qg6+ Kf3) -2.19/19 7} Qf4 {(Qf4) 4.25/20 11} 77. Qa2 {(Qa2 e4 Kb7 g3 Kc8 Qe5 Kb7 Kf4 Qf7+ Kg5 Qg8+ Kh6 Ka8 e3 Qf8+ Kg5 Qg8+ Kf5 Qh7+ Ke6 Qg8+ Kd6 Qg6+ Kd5 Qd3+ Qd4) -2.25/20 7} Qd4 {(Qd4) 4.70/18 10} 78. Kb7 {(Kb7 Qd2 Qb3+ Kf2 Qc4 Kg3 Qc7 Qxg2+ Kc8 Qd5 Kb8 Qb3+ Kc8 Kf4 Qc1+ Kf5 Qf1+ Qf3 Qc4 g3 Qf7+ Ke4 Qc4+ Ke3 Qb3+ Kf4) -2.61/18 10} Qd2 {(Qd2 Qa7+ Kf4 Qa3 Qxg2+ Kc7 Qc2+ Kd8 g3 Qa6 Kg4 Qe6+ Qf5 Qd5 e4 Qd1+ Qf3 Qd7+ Kh4 Qh7+ Kg5 Qg7+ Kf4 Qc7+ Ke3) 5.13/18 12} 79. Qb1 {(Qb1 Qxg2+ Kc7 Qd5 Qg6 Qc4+ Kb8 Qe4 Qh6+ Kf2 Qh2+ Kf3 Qh1+ Kf4 Qh6+ Kg3 Qd2 Qd4 Qc1 Kh2 Kc8 g3 Qh6+ Kg1 Qc6 g2 Qf3) -3.07/18 14} Qxg2+ {(Qxg2+ Kb8 Qe2 Qg1+ Kf4 Qc1+ Qe3 Qc7 Kf3 Kb7 Kg2 Qc2+ Qf2 Qa4 g3 Qc4 e4 Qd5 Qf3 Qa2+ Kh3 Qe6+ Kh2 Qe5 e3+) 5.58/19 9} 80. Kc7 {(Kc7 Qd5 Qg6 Qc4+ Kb8 Qe4 Qh6+ Kf3 Qh1+ Kf4 Qh6+ Kg3 Qd2 Qd4 Qe1+ Kh2 Qh4+ Kg2 Ka8 Qd5+ Ka7 Qf3 Ka6 e4 Kb5 e3 Kc5) -3.07/18 8} Qe2 {(Qe2 Qg1+ Kf4 Qc1+ Qe3 Qh1 e4 Kd7 g3 Qh3 Kf3 Ke8 Kf2 Qh8 g2 Qf6+ Ke2 Qa6+ Qd3 Qa2+ Kf3 Qf7+ Ke3 Qg6 Kf2) 6.12/19 10} 81. Qg6 {(Qg6 Kf2 Qf5+ Kg2 Qh5 Qe4 Kd8 g3 Kc7 Qc4+ Kb6 Qd4+ Kb5 e4 Kc6 e3 Qb5 Qc3+ Kb7 Qg7+ Ka6 Kf3) -3.25/17 6} Kf2 {(Kf2) 9.03/19 12} 82. Qh6 {(Qh6 e4 Qh2+ Kf3 Qh1+ Kf4 Qh6+ Kg3 Qd6+ Kg2 Qd5 Qd3 Qg8 g3 Qa2+ Kf3 Qf7+ Ke3 Qg7 Qc4+ Kb8 Qb4+ Ka7 Qc5+ Ka8) -3.25/17 10} Kg2 {(Kg2 Qc1) 12.59/19 10} 83. Qe6 {(Qe6 e4 Qd5 Qf3 Qd2+ Kg3 Qe1+ Kh3 Qb4 e3 Kc8 Kg2 Kb8 Qf2 Kb7 e2 Qxg4+ Kf1 Qh3+ Qg2+ Qxg2+ Kxg2 Kc6 e1=Q) -10.00/20 12} e4 {(e4 Qc6 g3 Kd7 Kh2 Ke6 g2 Qc7+ Kh1 Qh7+ Kg1 Qh3 Qd3 Qf5 Qf3 Qc5+ Kh2 Qd6+ Kh1 Ke7 g1=Q Qh6+ Kg2 Ke8 Qg3) 12.78/15 8} 84. Qd5 {(Qd5 Qf3 Qd2+ Kg3 Qe1+ Kh3 Kb6 e3 Ka5 e2 Ka4 Kg2 Qb4 Qc6+ Ka3 Qc1+ Ka2 e1=Q Qxg4+ Kf1 Kb3 Qe2 Qxe2+ Kxe2) -10.97/20 10} 0-1[/pgn]

[OliverBr]

Another issue: Why can't xboard (4.9.1) load the game and display the moves? What's wrong?

[OliverBr]

Also very strange since a long time: All other engines in the Amateur Division 11 are utterly outclassed when OliThink plays them on a linux server or locally.

With the same opening as above and white, OliThink won 10 of 10 games handily against Qapla.
Also a bulk test against it shows that there is about 118 ELO difference between OliThink and Quapla:

Code: Select all

   # PLAYER             :  RATING  ERROR  POINTS  PLAYED   (%)     W    D     L  D(%)  CFS(%)
   1 OliThink 5.11.4    :       0   ----  2295.0    3466  66.2  1892  806   768  23.3     100
   2 Qapla 0.3.2        :    -118     10  1171.0    3466  33.8   768  806  1892  23.3     ---

White advantage = 24.94 +/- 5.57
Draw rate (equal opponents) = 25.14 % +/- 0.75

Same for OliThink and Dumb, even 137 ELO:

Code: Select all

   # PLAYER             :  RATING  ERROR  POINTS  PLAYED   (%)     W    D     L  D(%)  CFS(%)
   1 OliThink 5.11.4    :       0   ----  2087.0    3047  68.5  1779  616   652  20.2     100
   2 Dumb 2.3           :    -137     12   960.0    3047  31.5   652  616  1779  20.2     ---

White advantage = 22.34 +/- 6.04
Draw rate (equal opponents) = 22.30 % +/- 0.80

In those tournaments Dumb and Qapla perform better than Olithink. I have seen it live. Example above.
What exactly is bringing the performance of OliThink so down in those tournaments? Can it be just the CPU? Smaller Level 1 Cache? But 130 ELO??

[OliverBr]

Another issue: Why can't xboard (4.9.1) load the game and display the moves? What's wrong?

It was actually a missing line break. Once I added about 3 linebreaks, the pgn loaded. Strange bug for a great software.

[OliverBr]

Now back to the endgame issue. Once i could load the pgn into xboard and have Stockfish 15.1 analyze it, I was right in my assumption:

OliThink was +5.79 before after Move 56.
I am not sure how many play chess here, I am only a mediocre player (let's say 1800 ELO), but I was sure I would win this against easily:
Here the position after 56...Kf6:

[d]8/3R4/p4k2/2pPp2p/1p2K1p1/1P1P2P1/r1P3P1/8 w - - 3 57

And here Stockfish's analysis:

Code: Select all

37	+5.90 	423.5M	6:09.49	Rd6+ Kg7 Re6 Kf7 Rh6 Kg7 d6 Kxh6 d7 Ra1 d8=Q Rf1 Kd5 Rf5 Qd6+ Kg7 Qe7+ Kg6 Qe6+ Kg5 Kxc5 a5 Qg8+ Kh6 Kb6 Rg5 Qh8+ Kg6 Kxa5 Rf5 Qe8+ Kg7 Qe7+ Kh8 Qe6 Rf1 Qh6+ Kg8 Qg6+ Kf8 Qxh5 Kg7 Qg5+ Kh7 Qe7+ Kg6 
36	+5.79 	326.3M	4:43.62	Rd6+ Kg7 Re6 Kf7 Rh6 Kg7 d6 Kxh6 d7 Ra1 d8=Q Rf1 Kd5 Rf5 Qd6+ Kg7 Qe7+ Kg6 Qe6+ Kg5 Kxc5 a5 Qg8+ Kh6 Kb6 Rg5 Qh8+ Kg6 Kxa5 Rf5 Ka4 Rf7 Qe8 Kf6 Ka5 Rb7 Qxh5 Rb8 Ka4 Ra8+ Kb5 Rb8+ Ka5 

Now, for whatever reasons, OliThink assumpts score 0.00 (???) the next moves thus plays bad moves, because "it's draw anyway".
Here: Instead of e.g. Rd6+ it plays Rh7 (???) and loses the all advantage at once.

Now Stockfish says: the complete advantage is gone:

Code: Select all

53	  0.00 	231.2M	4:29.00	Rxc2 d6 Re2+ Kd5 Rd2 Rh6+ Kf7 Ke4 Rd1 d7 Ke7 Rd6 Kd8 Kxe5 Rd2 Ke6 Re2+ Kd5 Rxg2 Kc6 Rf2 Rh6 Rf8 Rxh5 Rf6+ Kxc5 Rf3 Rd5 Rxg3 Kc6 Rf3 Rd6 Rf8 Rg6 a5 d4 a4 bxa4 b3 Rxg4 b2 Rg1 Rf6+ Kd5 Kxd7 Rb1 Rd6+ Kc4 Rc6+ Kb5 Rd6 Rxb2 Rxd4 a5
 

It is draw until move 63, where Stockfish suggests d7:

Code: Select all

59	  0.00 	27.0M  	0:26.05	d7 Rd3 Rh6 Ke7 Rh7+ Kf6 Rh6+ Ke7 

I remember well this move because I was sure, 63. d7 would be played, but no... it's 63. Rh7 (???). This time the draw score would be correct for 63. d7, but not for 63. Rh7.

Game lost, next move and score for Black:

Code: Select all

36	+5.26 	168.5M	2:50.76	Kg6 Ra7 Rxg3 Rxa6 Rd3 d7 Kf7 Rb6 Ke7 Kxc5 Rd4 Rb7 b3 Rxb3 Kxd7 Rb6 Ke7 Rg6 Kf7 Rh6 Rd2 Kc4 Rxg2 Kd3 Rf2 Ke4 Rf1 Kxe5 g3 Rh7+ Kg6 Rh3 Rf5+ Ke4 g2 Rg3+ Rg5 Rxg2 Rxg2 Kf4 

Now, who can help with this issue? Doesn't it happen with other engines maybe? Did you encounter such problems? I would like to hear experiences.

[OliverBr]

Now the first blund is 100% connected with a repetition score:

Code: Select all

55. Rxd6+ ... Kf7
56. Rd7+  ...  Kf6

Now if:

Code: Select all

57. Rd6+ ... Kf7

It would be a two time repetition and therefore 57. Rd6+ is not played (in order to avoid 3-fold repetition). I have changed the repetition scoring before but didn't bring anything. Maybe I have to look closer.

How exactly is the correct way to store a repetition score into a TT-Hashtable? It doesn't know how many times this position existed before or does it?
PS: I see now that this is actually an issue. Funny that all those new engines probably handle it correctly, while a decades old engine does not.

[Bjoern]

Hi,

I'm am not looking at other sources, probably there's a better solution than mine.

In TT I store also the distance from root-position. If the distance from root is higher than
the one in TT, I do not overwrite the score. This avoids false scores in the TT in my case.

Looking forward to omit ths TT data in the future....

Best regards
Björn

[OliverBr]

Hi Björn,

thank you for your reply. I will look into it.

But actually I have learned that the repetition/tt-table issue is actually not the reason for 57. Rh7.
The engine is actually thinking it is the best move. And it's not alone, a lot of strong (non-NNUE) engines share this opinion until quite late.
Even Stockfish goes for it first. But 57. Rh7 throws away the win. This is most disturbing.
So maybe 57. Rh7 was a difficult move in a difficult endgame.

But this doesn't justify 63. Rh7 instead of 63. d7. Because this move prefered by most engined and by the naked human eye.

Maybe it's solved like this:

Code: Select all

if (move == 'Rh7') score -= 32; 

[OliverBr]

This looks reasonable now: OliThink comes only to 63. Rh7 with TT-Hashtable pruning. Without it, it moves 63. d7 or 63 Rxe5, both resulting in a draw.

[OliverBr]

This looks reasonable now: OliThink comes only to 63. Rh7 with TT-Hashtable pruning. Without it, it moves 63. d7 or 63 Rxe5, both resulting in a draw.

But the TT-pruning wasn't the reason. It's just accidental that changing anything in the search/eval yields to other moves than 63. Rh7. It looks as it's another issue. In this case a endgame table or a neural net would avoid a bad move.