[fen]8/8/4p3/2k5/6p1/P5r1/2K5/R7 b - - 1 53 [/fen]
Blacks only winning move is Kd4. This position is from the example game from the RomiChess CPW page. The Romi version from 2006 did not find the winning move. Instead it played Kc4. The current version finds Kd4 but not till depth 25.
24 00:11 116,004k 10,185k +2.73 c5c4 a1e1 g3g2 c2d1 c4d5 e1e3 e6e5 d1e1 d5e6 e3e2 g2g3 e2a2 e5e4 a3a4 e4e3 a2h2 g3h3 h2g2 g4g3 a4a5 e6d5 a5a6 h3h1 e1e2 h1h2 g2h2
25 03:28 2,184,232k 10,464k +2.21 c5d4 a3a4 g3c3 c2d2 c3h3 a1g1 g4g3 a4a5 e6e5 d2c2 e5e4 a5a6 h3h2 c2b3 h2h6 g1d1 d4e5 d1a1
And the time goes from 00:11 to 03:28. And even SF15 does not see an overwhelming win for Kd4 right away.
So I'm wondering what is going on and how other engines handle this position? And what might be done to improve upon this?
Romi sacks a pawn on move 17 that SF15 thinks is okay and eventually gets a winning position.
A Curious Position
Moderator: Ras
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- Full name: Michael J Sherwin
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Re: A Curious Position
"And even SF15 does not see an overwhelming win for Kd4 right away."
Well, SF15 on my iPad, immediately eval -6.4 (depth 20)...
Well, SF15 on my iPad, immediately eval -6.4 (depth 20)...

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Re: A Curious Position
FEN: 8/8/4p3/2k5/6p1/P5r1/2K5/R7 b - - 1 53
Stockfish_15_x64_avx2:
NNUE evaluation using nn-6877cd24400e.nnue enabled
1/1 00:00 1k 1,205k +4.57 Kc5-c4
2/2 00:00 3k 2,569k +1.44 Rg3-e3 a3-a4
3/3 00:00 5k 4,878k +2.63 Kc5-c4 Ra1-e1 Rg3-g2+ Kc2-c1
4/4 00:00 9k 4,706k +2.12 Kc5-c4 Kc2-d2 Kc4-d4 Kd2-c2
5/5 00:00 11k 5,691k +2.87 Kc5-c4 Kc2-d2 Kc4-d4
6/7 00:00 27k 13,314k +3.29 Rg3-f3 Ra1-g1 g4-g3 Kc2-d1 Rf3xa3
7/10 00:00 52k 17,373k +1.74 Rg3-f3 a3-a4 g4-g3 Kc2-d2 Kc5-d4 a4-a5 g3-g2 Kd2-e2
8/11 00:00 132k 26,382k +1.42 Kc5-d4 a3-a4 Rg3-h3 a4-a5 g4-g3 a5-a6 Rh3-h2+ Kc2-b3
I don't use an EGTB. And even if I did it would not be the engine finding it. It takes to ply 8 for SF15 without an EGTB to determine that Kd4 is best but even then the score returned is not an overwhelming win. In fact SF15 initially prefers Kc4 over Kd4.
https://www.youtube.com/watch?v=6xijhqU8r2A
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Re: A curious position.
Hello:
I analysed the position with SF 15 (default net) with 2 cores, Multi-PV = 7 and the full set of 3, 4 and 5-man Syzygy EGTB:
There were 15,064,343 TB hits up to depth 31. I want to point out that even with 5-man EGTB in a 7-man position, the drawing move 53. … ♚c4 is considered as winning and best move at depth 7 by SF 15.
Regards from Spain.
Ajedrecista.
I analysed the position with SF 15 (default net) with 2 cores, Multi-PV = 7 and the full set of 3, 4 and 5-man Syzygy EGTB:
Code: Select all
FEN: 8/8/4p3/2k5/6p1/P5r1/2K5/R7 b - - 1 53
Stockfish_15_x64_popcnt:
[...]
7/8 00:01 70.931 70.860 +0,07 Rg3e3 a3a4 Re3h3 a4a5 g4g3 a5a6 Rh3h8 a6a7
7/9 00:01 70.931 70.860 +0,09 Kc5b6 Kc2d2 Rg3b3 Ra1e1 Kb6a7 Kd2e2 Rb3xa3 Ke2f1
7/9 00:01 70.931 70.860 +0,64 Rg3h3 Ra1g1 g4g3 Kc2d3 g3g2+ Kd3e4
7/8 00:01 70.931 70.860 +0,65 e6e5 a3a4 Kc5c4 Kc2d2 Kc4d4 Kd2e2 Rg3h3 Ra1g1
7/8 00:01 70.931 70.860 +1,41 Rg3f3 a3a4 g4g3 Kc2d2 Kc5d4
7/11 00:01 70.931 70.860 +1,55 Kc5d4 a3a4 Rg3h3 a4a5 g4g3 a5a6 Rh3h2+ Kc2b3
7/8 00:01 70.931 70.860 +2,50 Kc5c4 Kc2d2 Kc4d4 Kd2c2 Rg3h3 a3a4 g4g3 a4a5
---------------------------------------------------------------------------
[...]
---------------------------------------------------------------------------
31/28 21:15 1.571.470.345 1.231.924 0,00 Rg3h3 Ra1g1 Kc5d4 Rg1xg4+ Kd4e3 Rg4g1 Rh3h6 Rg1e1+ Ke3d4 a3a4 e6e5 Re1d1+ Kd4e4 Rd1a1 Rh6h2+ Kc2c1 Rh2h1+ Kc1b2 Rh1xa1
31/23 21:15 1.571.470.345 1.231.924 0,00 Kc5d5 a3a4 Kd5e4 a4a5 Rg3g2+ Kc2c3 Rg2h2 a5a6 Rh2h8 a6a7 Rh8a8 Kc3d2 Ke4f3 Kd2e1 e6e5 Ra1a3+ Kf3g2 Ra3a2+ Kg2g3 Ra2a3+ Kg3h2 Ra3a2+
31/27 21:15 1.571.470.345 1.231.924 0,00 Rg3f3 a3a4 Kc5d4 a4a5 Rf3f2+ Kc2b3 g4g3 a5a6 Rf2f8 Ra1d1+ Kd4e3 Rd1e1+ Ke3f2 Re1xe6 g3g2 Re6g6 Rf8a8 Rg6f6+ Kf2e2 Rf6e6+ Ke2f3 Re6f6+ Kf3e4 Rf6g6 Ke4f3
31/29 21:15 1.571.470.345 1.231.924 0,00 Kc5c4 Kc2d2 e6e5 a3a4 Kc4d4 Kd2e2 Rg3h3 Ke2f2 e5e4 a4a5 e4e3+ Kf2g2 e3e2 a5a6 Rh3e3 a6a7 Re3e8 Kg2f2 g4g3+ Kf2f3 Kd4d3 Ra1a3+ Kd3c4 Ra3a1
31/29 21:15 1.571.470.345 1.231.924 0,00 e6e5 a3a4 Kc5c4 Kc2d2 Kc4d4 Kd2e2 Rg3h3 Ke2f2 e5e4 a4a5 e4e3+ Kf2g2 e3e2 a5a6 Rh3e3 a6a7 Re3e8 Kg2f2 g4g3+ Kf2f3 Kd4d3 Ra1a3+ Kd3c4 Ra3a1
31/33 21:15 1.571.470.345 1.231.924 0,00 Rg3e3 a3a4 g4g3 Kc2d2 Kc5d4 a4a5 g3g2 a5a6 Re3a3 Ra1xa3 g2g1Q Ra3a4+ Kd4c5 a6a7 Qg1g2+ Kd2e1 Qg2a8 Ke1f2 Kc5c6 Kf2e3 Kc6d6 Ke3e2 Kd6e7 Ke2f2 Ke7f7 Ra4a5 Kf7g6 Ra5a4
31/42 21:15 1.571.470.345 1.231.924 +19,50 Kc5d4 a3a4 Rg3h3 a4a5 g4g3 a5a6 Rh3h2+ Kc2b3 Rh2h8 Ra1d1+ Kd4e4 Rd1e1+ Ke4f5 Kb3c4 Rh8a8 Kc4b5 e6e5 Kb5b6 Ra8g8 Re1g1 Kf5f4 Rg1f1+ Kf4g4 Rf1g1 Kg4f3 Rg1f1+ Kf3e2 Rf1a1 g3g2 Kb6c6 g2g1Q a6a7 Qg1xa1 Kc6d6 Qa1xa7 Kd6xe5
Regards from Spain.
Ajedrecista.
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Re: A Curious Position
Indeed no EGTB...