An endgame testposition

[Peter Berger]

[pgn][Event "Computer chess game"]
[Site ""]
[Date "2022.03.21"]
[Round "?"]
[White ""]
[Black ""]
[Result "*"]
[BlackElo "2400"]
[Time "20:20:12"]
[WhiteElo "2400"]
[TimeControl "7200+10"]
[SetUp "1"]
[FEN "3n1k2/p2B4/Pp1P2pp/1P1ppp2/7P/4P1P1/5PK1/8 w - - 0 1"]
[Termination "unterminated"]
[PlyCount "32"]
[WhiteType "human"]
[BlackType "human"]

1. Bc6 Nxc6 2. bxc6 Ke8 3. Kf3 b5 4. Ke2 e4 5. Kd2 d4 6. Kc2 g5 7. hxg5
hxg5 8. Kb3 Kd8 9. Kc2 b4 10. exd4 g4 11. Kb3 f4 12. gxf4 g3 13. fxg3 e3
14. Kc2 b3+ 15. Kc3 e2 16. Kd2 b2 *[/pgn]
One possible outcome.

Your line is way too complicated (if nice), Ed – it’s +really+ not that difficult. After 8. Kb3 black just goes 8. .. f4, and it is game over at once.
The human knowledge here is, that two passers defend each other in pawn endgames if they are not too close, so we don’t have to search this. This also answers Spliffjiffer’s question: no Zugzwang involved here at all.
And yes. Jouni – it is 1. f4 for the draw indeed. To be fair, +this+ one is probably slightly more difficult for humans, but it can be understood.
Source for this position is a game TogaIV 1.1 – Stockfish 130323:
[Event "Lang 120min+10sek"]
[Site "Berlin"]
[Date "2022.03.18"]
[Round "?"]
[White "Toga IV 1.1"]
[Black "Stockfish 230322"]
[Result "0-1"]
[ECO "D10"]
[PlyCount "96"]
[TimeControl "7200+10"]

{5120MB, LAPTOP-NCDN8BTK} 1. d4 {[%eval 16,24] [%emt 0:03:07]} d5 {[%emt 0:00:
10]} 2. c4 {[%eval 20,25] [%emt 0:04:35]} c6 {[%emt 0:00:09] (e6)} 3. cxd5 {
[%eval 33,25] [%emt 0:04:41]} cxd5 {[%emt 0:00:08]} 4. Bf4 {[%eval 37,26]
[%emt 0:03:12]} Nc6 {[%emt 0:00:09] (Sf6)} 5. e3 {[%eval 30,26] [%emt 0:04:08]}
Nf6 {[%emt 0:00:08]} 6. Bb5 {[%eval 27,25] [%emt 0:02:45]} Bg4 {[%emt 0:11:47]}
7. Nf3 {[%eval 31,28] [%emt 0:00:01]} e6 {[%emt 0:01:23]} 8. O-O {[%eval 32,27]
[%emt 0:02:12]} Bd6 {[%emt 0:02:11]} 9. Bxd6 {[%eval 36,28] [%emt 0:00:43]}
Qxd6 {[%emt 0:01:12]} 10. Nbd2 {[%eval 37,28] [%emt 0:01:18]} O-O {[%emt 0:00:
44] (Lxf3)} 11. Qa4 {[%eval 35,28] [%emt 0:03:23]} Bxf3 {[%emt 0:08:25]} 12.
Nxf3 {[%eval 40,29] [%emt 0:00:01]} Rfc8 {[%emt 0:11:26] (Se7)} 13. Rfc1 {
[%eval 43,29] [%emt 0:02:44]} Ne7 {[%emt 0:02:06]} 14. Rxc8+ {[%eval 45,29]
[%emt 0:01:37]} Nxc8 {[%emt 0:01:55]} 15. Rc1 {[%eval 42,29] [%emt 0:00:41]}
Nb6 {[%emt 0:02:23]} 16. Qa5 {[%eval 42,30] [%emt 0:00:26]} Rc8 {[%emt 0:08:23]
} 17. Rxc8+ {[%eval 36,31] [%emt 0:00:01]} Nxc8 {[%emt 0:02:25]} 18. Ne5 {
[%eval 37,29] [%emt 0:00:01]} Qb6 {[%emt 0:01:56]} 19. Qc3 {[%eval 35,28]
[%emt 0:00:21]} Qd8 {[%emt 0:01:27]} 20. Bd3 {[%eval 34,28] [%emt 0:02:50]} g6
{[%emt 0:03:35] (Sd7)} 21. g3 {[%eval 30,30] [%emt 0:02:15]} Nd7 {[%emt 0:07:
38]} 22. Nf3 {[%eval 31,36] [%emt 0:00:01]} Kg7 {[%emt 0:01:43] (Sd6)} 23. Kg2
{[%eval 30,33] [%emt 0:02:27]} h6 {[%emt 0:01:38] (Sd6)} 24. h3 {[%eval 30,31]
[%emt 0:03:10]} Nd6 {[%emt 0:01:52]} 25. h4 {[%eval 30,31] [%emt 0:01:25]} Nf6
{[%emt 0:02:01] (Db6)} 26. Qc5 {[%eval 30,29] [%emt 0:02:00]} Nc8 {[%emt 0:01:
58] (a6)} 27. a3 {[%eval 30,29] [%emt 0:02:04]} Ng4 {[%emt 0:01:13] (Sd7)} 28.
b4 {[%eval 28,26] [%emt 0:03:28]} Nf6 {[%emt 0:01:43] (Sd6)} 29. a4 {[%eval 21,
26] [%emt 0:02:02]} Nd7 {[%emt 0:00:09] (b6)} 30. Qc2 {[%eval 20,31] [%emt 0:
01:51]} Nd6 {[%emt 0:02:48]} 31. Ne5 {[%eval 17,28] [%emt 0:00:01]} Nxe5 {
[%emt 0:02:04]} 32. dxe5 {[%eval 38,29] [%emt 0:00:01]} Nf5 {[%emt 0:02:21]}
33. a5 {[%eval 26,28] [%emt 0:00:01]} Ne7 {[%emt 0:01:36] (Df8)} 34. Qc5 {
[%eval 60,32] [%emt 0:02:50]} b6 {[%emt 0:00:09] (Sc8)} 35. Qd6 {[%eval 21,34]
[%emt 0:02:03]} Qxd6 {[%emt 0:01:39]} 36. exd6 {[%eval 21,34] [%emt 0:00:01]}
Nc6 {[%emt 0:02:06]} 37. Bb5 {[%eval 18,35] [%emt 0:00:33]} Nd8 {[%emt 0:01:43]
} 38. a6 {[%eval 6,29] [%emt 0:00:56]} Kf8 {[%emt 0:00:24] (f5)} 39. Bd7 {
[%eval 16,33] [%emt 0:02:37]} e5 {[%emt 0:00:08]} 40. b5 {[%eval 14,32] [%emt
0:01:27]} f5 {[%emt 0:01:27]} 41. Bc6 {[%eval 13,34] [%emt 0:00:10]} Nxc6 {
[%emt 0:01:42] (d4)} 42. bxc6 {[%eval 216,28] [%emt 0:01:37]} Ke8 {[%emt 0:01:
32]} 43. Kf3 {[%eval 216,32] [%emt 0:00:18]} b5 {[%emt 0:02:24] (Kd8)} 44. Ke2
{[%eval 216,34] [%emt 0:02:33]} e4 {[%emt 0:00:08] (b4)} 45. Kd2 {[%eval 0,23]
[%emt 0:01:30]} d4 {[%emt 0:00:15] (b4)} 46. Kc2 {[%eval 0,26] [%emt 0:02:15]}
g5 {[%emt 0:01:48] (d3+)} 47. hxg5 {[%eval -751,25] [%emt 0:25:58]} hxg5 {
[%emt 0:00:35]} 48. exd4 {[%eval -767,17] [%emt 0:00:33]} f4 {[%emt 0:01:12]
(Kd8)} 0-1

[Scally]

…very interesting.

I tried my Huntsman compile on my 8GB Raspberry Pi 4 used for Picochess.

I wasn’t sure wether to add the endgame databases or not, but the results were similar showing that only f4 can draw …

Code: Select all

info depth 38 seldepth 54 multipv 1 score cp -31 nodes 7168877563 nps 413757 hashfull 998 tbhits 1530828 time 17326299 pv f2f4 e5f4 g3f4 d8f7 d7c6 f7d6 g2f3 f8e7 f3e2 d6e4 e2d3 g6g5 h4g5 h6g5 f4g5 e4g5 c6d5 e7d6 d3d4 g5e6 d4c4 d6e5 d5f3 e6g5 f3c6 g5f7 c4d3 f7d6 d3c3 d6e4 c3c4 e4f6 c6b7 f6g8 c4d3 g8h6 b7g2 h6g4 g2f3 g4f6 f3g2
info depth 38 seldepth 70 multipv 2 score cp -251 nodes 7168877563 nps 413757 hashfull 998 tbhits 1530828 time 17326299 pv d7c8 d8f7 d6d7 f8e7 c8b7 d5d4 e3d4 e5d4 f2f4 e7d7 g2f3 d7d6 h4h5 g6h5 b7c8 d6c5 c8f5 f7d6 f5d3 c5b4 f4f5 b4c3 f3e2 d6e8 d3e4 e8f6 e4g2 d4d3 e2e3 d3d2 g2f3 f6g4 e3e4 c3c4 f3e2 c4c5 e4d3 c5b5 d3d2 b5c5 d2c3 g4e3 e2d3 e3d5 c3b3 d5f6 b3a4 f6e8 d3e4 c5d4 a4b5 h5h4 b5c6 h4g3 c6b7 d4e5 e4c6 b6b5 c6e8 b5b4 b7a7 b4b3 a7b7 b3b2 a6a7
info depth 37 seldepth 54 multipv 3 score cp -297 nodes 7168877563 nps 413757 hashfull 998 tbhits 1530828 time 17326299 pv g3g4 f5g4 d7g4 d8f7 d6d7 f8e7 g4f3 e5e4 f3g4 f7d6 g4e6 d6b5 e6d5 b5c3 d5f7 e7d7 f7g6 b6b5 g2f1 d7e6 f1e1 b5b4 e1d2 e6d5 d2c2 d5c4 g6f7 c4b5 c2b3 c3d1 f7e8 b5c5 e8g6 d1f2 g6f5 c5b5 f5d7 b5a5 d7f5 f2d1 f5g6 d1e3 g6e4 e3f1 b3c4 a5a4 e4g6 f1e3 c4d3

Cheers,

Al.