Mate in 19 shortened to mate in 17 by The Huntsman 1

[acase]

This on is in the ChestUCI database:

[pgn][Event "Mate in 17"] [Site "Columbus, Ohio"] [Date "2024.01.23"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "17:05:48"] [TimeControl "0"] [SetUp "1"] [FEN "6B1/4K1p1/4P1pb/N1p3pq/1pP3kr/1P1p1R1p/3N3B/8 w - - 0 1"] [Termination "normal"] [PlyCount "33"] [WhiteType "program"] [BlackType "program"] [Comment "bm #19; 00:00 @ C2/R-4/K2/P3/X4;"] 1. Rxd3 {+M17/84 302 The Huntsman 1 bmi2} Kf5 2. Rd5+ Kg4 3. Rd8 Kf5 4. Rf8+ Kg4 5. Bf7 Kf5 6. Be8+ Kg4 7. Kf7 Kf5 8. Bd7 Rf4 9. Kg8+ Kg4 10. e7+ Kh4 11. Rxf4+ gxf4 12. e8=Q Qg5 13. Nf3+ Kh5 14. Nxg5 Bxg5 15. Kh7 Kh4 16. Qe6 Kh5 17. Qg4# 1-0 [/pgn]

Here is a link to this problem----->https://www.yacpdb.org/#67680

[acase]

Here's another mate in 19 shortened to mate in 18 from the ChestUCI database:

[pgn][Event "Mate in 18"] [Site "Columbus, Ohio"] [Date "2024.01.23"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "19:10:12"] [TimeControl "0"] [SetUp "1"] [FEN "8/1p2p3/1P2P3/4p2R/8/4pppK/3prqp1/B2Rbbkn w - - 0 1"] [Termination "normal"] [PlyCount "35"] [WhiteType "program"] [BlackType "program"] [Comment "bm #19; Duals(4); 00:03 @ C2/R0/K2/P1/X1;"] 1. Bc3 e4 2. Bf6 exf6 3. e7 f5 4. e8=Q f4 5. Kh4 Kh2 6. Kg4+ Kg1 7. Ra5 Kh2 8. Qh8+ Kg1 9. Ra6 bxa6 10. b7 a5 11. b8=N a4 12. Nd7 a3 13. Nf8 a2 14. Ng6 a1=Q 15. Qxa1 Kh2 16. Qh8+ Kg1 17. Nh4 Kh2 18. Nxf3# 1-0 [/pgn]

So perhaps there's no duals afterall?

[acase]

Here's a mate in 19 from the same database knocked down to a mate in 15:

[pgn][Event "Mate in 15"] [Site "Columbus, Ohio"] [Date "2024.01.23"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "19:26:00"] [TimeControl "0"] [SetUp "1"] [FEN "8/1p5p/1pp3p1/1k6/1p5p/1P5P/6pP/Q5Kb w - - 0 1"] [Termination "normal"] [PlyCount "29"] [WhiteType "program"] [BlackType "program"] [Comment "bm #19; --:-- @ C2/R0/K4/P4/X7;"] 1. Qg7 Ka6 2. Qxh7 g5 3. Qg7 Ka7 4. Qxg5 c5 5. Qxh4 Kb8 6. Qd8+ Ka7 7. Qc8 c4 8. Qxc4 Kb8 9. h4 b5 10. Qc5 Ka8 11. h5 b6 12. Qe7 Kb8 13. h6 Kc8 14. h7 Kb8 15. h8=Q# 1-0 [/pgn]

[Jouni]

Stockfish is tested with these 6560 positions https://github.com/vondele/matetrack/bl ... dtrack.epd. But I am not sure how much checking for correctness is done?

[Ajedrecista]

Hello Andrew:

Here's another mate in 19 shortened to mate in 18 from the ChestUCI database:

[pgn][Event "Mate in 18"] [Site "Columbus, Ohio"] [Date "2024.01.23"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "19:10:12"] [TimeControl "0"] [SetUp "1"] [FEN "8/1p2p3/1P2P3/4p2R/8/4pppK/3prqp1/B2Rbbkn w - - 0 1"] [Termination "normal"] [PlyCount "35"] [WhiteType "program"] [BlackType "program"] [Comment "bm #19; Duals(4); 00:03 @ C2/R0/K2/P1/X1;"] 1. Bc3 e4 2. Bf6 exf6 3. e7 f5 4. e8=Q f4 5. Kh4 Kh2 6. Kg4+ Kg1 7. Ra5 Kh2 8. Qh8+ Kg1 9. Ra6 bxa6 10. b7 a5 11. b8=N a4 12. Nd7 a3 13. Nf8 a2 14. Ng6 a1=Q 15. Qxa1 Kh2 16. Qh8+ Kg1 17. Nh4 Kh2 18. Nxf3# 1-0 [/pgn]

So perhaps there's no duals afterall?

Chest solutions (four duals in #19) of one move longer happen because the b-pawn underpromotes to bishop instead of to knight. Anyway, at least Bb2 and Bc3 should lead to #18, so there are still duals (if I understand 'dual' correctly).

------------

Here's a mate in 19 from the same database knocked down to a mate in 15:

[pgn][Event "Mate in 15"] [Site "Columbus, Ohio"] [Date "2024.01.23"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "19:26:00"] [TimeControl "0"] [SetUp "1"] [FEN "8/1p5p/1pp3p1/1k6/1p5p/1P5P/6pP/Q5Kb w - - 0 1"] [Termination "normal"] [PlyCount "29"] [WhiteType "program"] [BlackType "program"] [Comment "bm #19; --:-- @ C2/R0/K4/P4/X7;"] 1. Qg7 Ka6 2. Qxh7 g5 3. Qg7 Ka7 4. Qxg5 c5 5. Qxh4 Kb8 6. Qd8+ Ka7 7. Qc8 c4 8. Qxc4 Kb8 9. h4 b5 10. Qc5 Ka8 11. h5 b6 12. Qe7 Kb8 13. h6 Kc8 14. h7 Kb8 15. h8=Q# 1-0 [/pgn]

This problem can be found here:

https://www.yacpdb.org/#344422

IMHO, the beauty of this problem is not the shortest DTM, but the queen triangulation a1-h8-a8. Anyway, SF 16 on my modest hardware finally agrees on #15 (at least with Qg7 and Qh8):

Code: Select all

FEN: 8/1p5p/1pp3p1/1k6/1p5p/1P5P/6pP/Q5Kb w - - 0 1

Stockfish_16-windows-x86-64-modern:
[...]
---------------------------------------------------------------------------
 55/34	07:35	 859.121.511	1.885.903	+M17	Qa1c1 Kb5a6 Qc1c4+ Ka6a7 Qc4xh4 h7h5 Qh4g3 c6c5 Qg3xg6 h5h4 Qg6g5 c5c4 Qg5xh4 c4xb3 Qh4f2 Ka7a6 h3h4 Ka6b5 h4h5 Kb5c4 Qf2b2 Kc4b5 h5h6 Kb5c4 h6h7 Kc4b5 h7h8Q Kb5c6 Qh8e8+ Kc6c5 Qb2e5+ Kc5c4 Qe8b5+
 55/32	07:35	 859.121.511	1.885.903	+M16	Qa1e5+ Kb5a6 Qe5g7 b6b5 Qg7xh7 g6g5 Qh7f5 Ka6b6 Qf5xg5 c6c5 Qg5xh4 c5c4 Qh4f2+ Kb6c6 h3h4 c4xb3 h4h5 b3b2 Qf2xb2 Kc6d7 h5h6 b7b6 h6h7 b4b3 h7h8Q Kd7c6 Qb2c3+ Kc6d7 Qc3e5 b3b2 Qh8e8+
 55/32	07:35	 859.121.511	1.885.903	+M16	Qa1d4 Kb5a6 Qd4xh4 h7h5 Qh4g5 h5h4 Qg5xh4 c6c5 Qh4g5 c5c4 Qg5xg6 c4xb3 Qg6d3+ b6b5 Qd3xb3 Ka6b6 h3h4 Kb6c7 h4h5 Kc7d6 h5h6 Kd6c6 h6h7 Kc6b6 h7h8Q Kb6a7 Qb3xb4 Ka7b6 Qb4d6+ Kb6a5 Qh8a8+
 55/32	07:35	 859.121.511	1.885.903	+M16	Qa1e1 Kb5a6 Qe1xh4 h7h5 Qh4g5 h5h4 Qg5xh4 c6c5 Qh4g5 c5c4 Qg5xg6 c4xb3 Qg6d3+ b6b5 Qd3xb3 Ka6b6 h3h4 Kb6c7 h4h5 Kc7d6 h5h6 Kd6c6 h6h7 Kc6b6 h7h8Q Kb6a7 Qb3xb4 Ka7b6 Qb4d6+ Kb6a5 Qh8a8+
 55/32	07:35	 859.121.511	1.885.903	+M16	Qa1f6 c6c5 Qf6xh4 g6g5 Qh4xg5 Kb5c6 h3h4 c5c4 Qg5h6+ Kc6d5 Qh6xh7 c4xb3 Qh7g6 b3b2 h4h5 b4b3 h5h6 b2b1Q+ Qg6xb1 b3b2 Qb1xb2 Kd5c4 h6h7 Kc4d5 h7h8Q Kd5c6 Qh8f6+ Kc6c7 Qb2xb6+ Kc7c8 Qb6d8+
 55/30	07:35	 859.121.511	1.885.903	+M15	Qa1h8 h7h5 Qh8g7 Kb5a6 Qg7xg6 b6b5 Qg6xh5 Ka6b6 Qh5xh4 c6c5 Qh4f2 Kb6c7 h3h4 c5c4 h4h5 c4xb3 Qf2b2 Kc7b6 h5h6 Kb6c5 h6h7 Kc5d5 h7h8Q Kd5c6 Qb2f6+ Kc6d5 Qf6d4+ Kd5e6 Qh8f6+
 55/30	07:35	 859.121.511	1.885.903	+M15	Qa1g7 Kb5a6 Qg7xh7 g6g5 Qh7f5 Ka6a7 Qf5xg5 c6c5 Qg5xh4 b6b5 Qh4f2 Ka7b6 h3h4 Kb6c6 h4h5 c5c4 h5h6 c4xb3 h6h7 b3b2 Qf2xb2 Kc6c5 h7h8Q Kc5c6 Qb2f6+ Kc6c5 Qf6d4+ Kc5c6 Qh8c8+

Regards from Spain.

Ajedrecista.

[acase]

Hello Andrew:

Here's another mate in 19 shortened to mate in 18 from the ChestUCI database:

[pgn][Event "Mate in 18"] [Site "Columbus, Ohio"] [Date "2024.01.23"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "19:10:12"] [TimeControl "0"] [SetUp "1"] [FEN "8/1p2p3/1P2P3/4p2R/8/4pppK/3prqp1/B2Rbbkn w - - 0 1"] [Termination "normal"] [PlyCount "35"] [WhiteType "program"] [BlackType "program"] [Comment "bm #19; Duals(4); 00:03 @ C2/R0/K2/P1/X1;"] 1. Bc3 e4 2. Bf6 exf6 3. e7 f5 4. e8=Q f4 5. Kh4 Kh2 6. Kg4+ Kg1 7. Ra5 Kh2 8. Qh8+ Kg1 9. Ra6 bxa6 10. b7 a5 11. b8=N a4 12. Nd7 a3 13. Nf8 a2 14. Ng6 a1=Q 15. Qxa1 Kh2 16. Qh8+ Kg1 17. Nh4 Kh2 18. Nxf3# 1-0 [/pgn]

So perhaps there's no duals afterall?

Chest solutions (four duals in #19) of one move longer happen because the b-pawn underpromotes to bishop instead of to knight. Anyway, at least Bb2 and Bc3 should lead to #18, so there are still duals (if I understand 'dual' correctly).

------------

Here's a mate in 19 from the same database knocked down to a mate in 15:

[pgn][Event "Mate in 15"] [Site "Columbus, Ohio"] [Date "2024.01.23"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "19:26:00"] [TimeControl "0"] [SetUp "1"] [FEN "8/1p5p/1pp3p1/1k6/1p5p/1P5P/6pP/Q5Kb w - - 0 1"] [Termination "normal"] [PlyCount "29"] [WhiteType "program"] [BlackType "program"] [Comment "bm #19; --:-- @ C2/R0/K4/P4/X7;"] 1. Qg7 Ka6 2. Qxh7 g5 3. Qg7 Ka7 4. Qxg5 c5 5. Qxh4 Kb8 6. Qd8+ Ka7 7. Qc8 c4 8. Qxc4 Kb8 9. h4 b5 10. Qc5 Ka8 11. h5 b6 12. Qe7 Kb8 13. h6 Kc8 14. h7 Kb8 15. h8=Q# 1-0 [/pgn]

This problem can be found here:

https://www.yacpdb.org/#344422

IMHO, the beauty of this problem is not the shortest DTM, but the queen triangulation a1-h8-a8. Anyway, SF 16 on my modest hardware finally agrees on #15 (at least with Qg7 and Qh8):

Code: Select all

FEN: 8/1p5p/1pp3p1/1k6/1p5p/1P5P/6pP/Q5Kb w - - 0 1

Stockfish_16-windows-x86-64-modern:
[...]
---------------------------------------------------------------------------
 55/34	07:35	 859.121.511	1.885.903	+M17	Qa1c1 Kb5a6 Qc1c4+ Ka6a7 Qc4xh4 h7h5 Qh4g3 c6c5 Qg3xg6 h5h4 Qg6g5 c5c4 Qg5xh4 c4xb3 Qh4f2 Ka7a6 h3h4 Ka6b5 h4h5 Kb5c4 Qf2b2 Kc4b5 h5h6 Kb5c4 h6h7 Kc4b5 h7h8Q Kb5c6 Qh8e8+ Kc6c5 Qb2e5+ Kc5c4 Qe8b5+
 55/32	07:35	 859.121.511	1.885.903	+M16	Qa1e5+ Kb5a6 Qe5g7 b6b5 Qg7xh7 g6g5 Qh7f5 Ka6b6 Qf5xg5 c6c5 Qg5xh4 c5c4 Qh4f2+ Kb6c6 h3h4 c4xb3 h4h5 b3b2 Qf2xb2 Kc6d7 h5h6 b7b6 h6h7 b4b3 h7h8Q Kd7c6 Qb2c3+ Kc6d7 Qc3e5 b3b2 Qh8e8+
 55/32	07:35	 859.121.511	1.885.903	+M16	Qa1d4 Kb5a6 Qd4xh4 h7h5 Qh4g5 h5h4 Qg5xh4 c6c5 Qh4g5 c5c4 Qg5xg6 c4xb3 Qg6d3+ b6b5 Qd3xb3 Ka6b6 h3h4 Kb6c7 h4h5 Kc7d6 h5h6 Kd6c6 h6h7 Kc6b6 h7h8Q Kb6a7 Qb3xb4 Ka7b6 Qb4d6+ Kb6a5 Qh8a8+
 55/32	07:35	 859.121.511	1.885.903	+M16	Qa1e1 Kb5a6 Qe1xh4 h7h5 Qh4g5 h5h4 Qg5xh4 c6c5 Qh4g5 c5c4 Qg5xg6 c4xb3 Qg6d3+ b6b5 Qd3xb3 Ka6b6 h3h4 Kb6c7 h4h5 Kc7d6 h5h6 Kd6c6 h6h7 Kc6b6 h7h8Q Kb6a7 Qb3xb4 Ka7b6 Qb4d6+ Kb6a5 Qh8a8+
 55/32	07:35	 859.121.511	1.885.903	+M16	Qa1f6 c6c5 Qf6xh4 g6g5 Qh4xg5 Kb5c6 h3h4 c5c4 Qg5h6+ Kc6d5 Qh6xh7 c4xb3 Qh7g6 b3b2 h4h5 b4b3 h5h6 b2b1Q+ Qg6xb1 b3b2 Qb1xb2 Kd5c4 h6h7 Kc4d5 h7h8Q Kd5c6 Qh8f6+ Kc6c7 Qb2xb6+ Kc7c8 Qb6d8+
 55/30	07:35	 859.121.511	1.885.903	+M15	Qa1h8 h7h5 Qh8g7 Kb5a6 Qg7xg6 b6b5 Qg6xh5 Ka6b6 Qh5xh4 c6c5 Qh4f2 Kb6c7 h3h4 c5c4 h4h5 c4xb3 Qf2b2 Kc7b6 h5h6 Kb6c5 h6h7 Kc5d5 h7h8Q Kd5c6 Qb2f6+ Kc6d5 Qf6d4+ Kd5e6 Qh8f6+
 55/30	07:35	 859.121.511	1.885.903	+M15	Qa1g7 Kb5a6 Qg7xh7 g6g5 Qh7f5 Ka6a7 Qf5xg5 c6c5 Qg5xh4 b6b5 Qh4f2 Ka7b6 h3h4 Kb6c6 h4h5 c5c4 h5h6 c4xb3 h6h7 b3b2 Qf2xb2 Kc6c5 h7h8Q Kc5c6 Qb2f6+ Kc6c5 Qf6d4+ Kc5c6 Qh8c8+

Regards from Spain.

Ajedrecista.

Hi Jesus,

You are correct about the duals, and yes the triangulation maneuver is the beauty of the "mate in 19", I'm just posting ones that can be shortened because I think some are interested if there is a shorter way which means the intended solution to the mate problem is kind of "cooked" or "corrected", like this Mate in 23 in the ChestUCI database that turns out to be a mate in 11:

[pgn][Event "Mate in 23"] [Site "Columbus, Ohio"] [Date "2024.01.24"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "20:11:50"] [TimeControl "0"] [SetUp "1"] [FEN "3R1nqb/B2n1prb/4pPp1/1p1kN1P1/1P2rP1K/2p5/2P1P3/7B w - - 0 1"] [Termination "normal"] [PlyCount "21"] [WhiteType "program"] [BlackType "program"] [Comment "bm #23; 00:00 @ C2/R0/K2/P1/X1;"] 1. Kg3 Kd6 2. Bb8+ Kd5 3. Kf2 Kd4 4. Nc6+ Kd5 5. Na5 Kd4 6. e3+ Kd5 7. Bg2 e5 8. Bc7 Ke6 9. Re8+ Kd5 10. Re7 Nxf6 11. Rxe5# 1-0 [/pgn]

https://www.yacpdb.org/#67687

Regards from the U.S.

[ImNotStockfish]

This on is in the ChestUCI database:

[pgn][Event "Mate in 17"] [Site "Columbus, Ohio"] [Date "2024.01.23"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "17:05:48"] [TimeControl "0"] [SetUp "1"] [FEN "6B1/4K1p1/4P1pb/N1p3pq/1pP3kr/1P1p1R1p/3N3B/8 w - - 0 1"] [Termination "normal"] [PlyCount "33"] [WhiteType "program"] [BlackType "program"] [Comment "bm #19; 00:00 @ C2/R-4/K2/P3/X4;"] 1. Rxd3 {+M17/84 302 The Huntsman 1 bmi2} Kf5 2. Rd5+ Kg4 3. Rd8 Kf5 4. Rf8+ Kg4 5. Bf7 Kf5 6. Be8+ Kg4 7. Kf7 Kf5 8. Bd7 Rf4 9. Kg8+ Kg4 10. e7+ Kh4 11. Rxf4+ gxf4 12. e8=Q Qg5 13. Nf3+ Kh5 14. Nxg5 Bxg5 15. Kh7 Kh4 16. Qe6 Kh5 17. Qg4# 1-0 [/pgn]

Here is a link to this problem----->https://www.yacpdb.org/#67680

This one was already improved by Stockfish Matefinder 9 back in 2018 and was already fixed in the ChestUCI database

https://groups.google.com/g/fishcooking ... voYQZUCQAJ

Code: Select all

6B1/4K1p1/4P1pb/N1p3pq/1pP3kr/1P1p1R1p/3N3B/8 w - - bm #17; SFMF9;

Here's another mate in 19 shortened to mate in 18 from the ChestUCI database:

[pgn][Event "Mate in 18"] [Site "Columbus, Ohio"] [Date "2024.01.23"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "19:10:12"] [TimeControl "0"] [SetUp "1"] [FEN "8/1p2p3/1P2P3/4p2R/8/4pppK/3prqp1/B2Rbbkn w - - 0 1"] [Termination "normal"] [PlyCount "35"] [WhiteType "program"] [BlackType "program"] [Comment "bm #19; Duals(4); 00:03 @ C2/R0/K2/P1/X1;"] 1. Bc3 e4 2. Bf6 exf6 3. e7 f5 4. e8=Q f4 5. Kh4 Kh2 6. Kg4+ Kg1 7. Ra5 Kh2 8. Qh8+ Kg1 9. Ra6 bxa6 10. b7 a5 11. b8=N a4 12. Nd7 a3 13. Nf8 a2 14. Ng6 a1=Q 15. Qxa1 Kh2 16. Qh8+ Kg1 17. Nh4 Kh2 18. Nxf3# 1-0 [/pgn]

So perhaps there's no duals afterall?

This one is more interesting, nice job!

Here's a mate in 19 from the same database knocked down to a mate in 15:

[pgn][Event "Mate in 15"] [Site "Columbus, Ohio"] [Date "2024.01.23"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "19:26:00"] [TimeControl "0"] [SetUp "1"] [FEN "8/1p5p/1pp3p1/1k6/1p5p/1P5P/6pP/Q5Kb w - - 0 1"] [Termination "normal"] [PlyCount "29"] [WhiteType "program"] [BlackType "program"] [Comment "bm #19; --:-- @ C2/R0/K4/P4/X7;"] 1. Qg7 Ka6 2. Qxh7 g5 3. Qg7 Ka7 4. Qxg5 c5 5. Qxh4 Kb8 6. Qd8+ Ka7 7. Qc8 c4 8. Qxc4 Kb8 9. h4 b5 10. Qc5 Ka8 11. h5 b6 12. Qe7 Kb8 13. h6 Kc8 14. h7 Kb8 15. h8=Q# 1-0 [/pgn]

This one was also marked as a mate in 15 in ChestUCI

Code: Select all

8/1p5p/1pp3p1/1k6/1p5p/1P5P/6pP/Q5Kb w - - bm #15; --:-- @ C2/R0/K4/P4/X7;

Stockfish is tested with these 6560 positions https://github.com/vondele/matetrack/bl ... dtrack.epd. But I am not sure how much checking for correctness is done?

It uses the matetrack file, not matedtrack. And a lot of checking for correctness is done, a lot of mates have been improved already and some had to be removed entirely for not being mates at all.

Hi Jesus,

You are correct about the duals, and yes the triangulation maneuver is the beauty of the "mate in 19", I'm just posting ones that can be shortened because I think some are interested if there is a shorter way which means the intended solution to the mate problem is kind of "cooked" or "corrected", like this Mate in 23 in the ChestUCI database that turns out to be a mate in 11:

[pgn][Event "Mate in 23"] [Site "Columbus, Ohio"] [Date "2024.01.24"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "20:11:50"] [TimeControl "0"] [SetUp "1"] [FEN "3R1nqb/B2n1prb/4pPp1/1p1kN1P1/1P2rP1K/2p5/2P1P3/7B w - - 0 1"] [Termination "normal"] [PlyCount "21"] [WhiteType "program"] [BlackType "program"] [Comment "bm #23; 00:00 @ C2/R0/K2/P1/X1;"] 1. Kg3 Kd6 2. Bb8+ Kd5 3. Kf2 Kd4 4. Nc6+ Kd5 5. Na5 Kd4 6. e3+ Kd5 7. Bg2 e5 8. Bc7 Ke6 9. Re8+ Kd5 10. Re7 Nxf6 11. Rxe5# 1-0 [/pgn]

https://www.yacpdb.org/#67687

Regards from the U.S.

This one was also marked as mate in 11 improved by SFMF9 in 2018

Code: Select all

3R1nqb/B2n1prb/4pPp1/1p1kN1P1/1P2rP1K/2p5/2P1P3/7B w - - bm #11; SFMF9;

[acase]

This on is in the ChestUCI database:

[pgn][Event "Mate in 17"] [Site "Columbus, Ohio"] [Date "2024.01.23"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "17:05:48"] [TimeControl "0"] [SetUp "1"] [FEN "6B1/4K1p1/4P1pb/N1p3pq/1pP3kr/1P1p1R1p/3N3B/8 w - - 0 1"] [Termination "normal"] [PlyCount "33"] [WhiteType "program"] [BlackType "program"] [Comment "bm #19; 00:00 @ C2/R-4/K2/P3/X4;"] 1. Rxd3 {+M17/84 302 The Huntsman 1 bmi2} Kf5 2. Rd5+ Kg4 3. Rd8 Kf5 4. Rf8+ Kg4 5. Bf7 Kf5 6. Be8+ Kg4 7. Kf7 Kf5 8. Bd7 Rf4 9. Kg8+ Kg4 10. e7+ Kh4 11. Rxf4+ gxf4 12. e8=Q Qg5 13. Nf3+ Kh5 14. Nxg5 Bxg5 15. Kh7 Kh4 16. Qe6 Kh5 17. Qg4# 1-0 [/pgn]

Here is a link to this problem----->https://www.yacpdb.org/#67680

This one was already improved by Stockfish Matefinder 9 back in 2018 and was already fixed in the ChestUCI database

https://groups.google.com/g/fishcooking ... voYQZUCQAJ

Code: Select all

6B1/4K1p1/4P1pb/N1p3pq/1pP3kr/1P1p1R1p/3N3B/8 w - - bm #17; SFMF9;

Here's another mate in 19 shortened to mate in 18 from the ChestUCI database:

[pgn][Event "Mate in 18"] [Site "Columbus, Ohio"] [Date "2024.01.23"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "19:10:12"] [TimeControl "0"] [SetUp "1"] [FEN "8/1p2p3/1P2P3/4p2R/8/4pppK/3prqp1/B2Rbbkn w - - 0 1"] [Termination "normal"] [PlyCount "35"] [WhiteType "program"] [BlackType "program"] [Comment "bm #19; Duals(4); 00:03 @ C2/R0/K2/P1/X1;"] 1. Bc3 e4 2. Bf6 exf6 3. e7 f5 4. e8=Q f4 5. Kh4 Kh2 6. Kg4+ Kg1 7. Ra5 Kh2 8. Qh8+ Kg1 9. Ra6 bxa6 10. b7 a5 11. b8=N a4 12. Nd7 a3 13. Nf8 a2 14. Ng6 a1=Q 15. Qxa1 Kh2 16. Qh8+ Kg1 17. Nh4 Kh2 18. Nxf3# 1-0 [/pgn]

So perhaps there's no duals afterall?

This one is more interesting, nice job!

Here's a mate in 19 from the same database knocked down to a mate in 15:

[pgn][Event "Mate in 15"] [Site "Columbus, Ohio"] [Date "2024.01.23"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "19:26:00"] [TimeControl "0"] [SetUp "1"] [FEN "8/1p5p/1pp3p1/1k6/1p5p/1P5P/6pP/Q5Kb w - - 0 1"] [Termination "normal"] [PlyCount "29"] [WhiteType "program"] [BlackType "program"] [Comment "bm #19; --:-- @ C2/R0/K4/P4/X7;"] 1. Qg7 Ka6 2. Qxh7 g5 3. Qg7 Ka7 4. Qxg5 c5 5. Qxh4 Kb8 6. Qd8+ Ka7 7. Qc8 c4 8. Qxc4 Kb8 9. h4 b5 10. Qc5 Ka8 11. h5 b6 12. Qe7 Kb8 13. h6 Kc8 14. h7 Kb8 15. h8=Q# 1-0 [/pgn]

This one was also marked as a mate in 15 in ChestUCI

Code: Select all

8/1p5p/1pp3p1/1k6/1p5p/1P5P/6pP/Q5Kb w - - bm #15; --:-- @ C2/R0/K4/P4/X7;

Stockfish is tested with these 6560 positions https://github.com/vondele/matetrack/bl ... dtrack.epd. But I am not sure how much checking for correctness is done?

It uses the matetrack file, not matedtrack. And a lot of checking for correctness is done, a lot of mates have been improved already and some had to be removed entirely for not being mates at all.

Hi Jesus,

You are correct about the duals, and yes the triangulation maneuver is the beauty of the "mate in 19", I'm just posting ones that can be shortened because I think some are interested if there is a shorter way which means the intended solution to the mate problem is kind of "cooked" or "corrected", like this Mate in 23 in the ChestUCI database that turns out to be a mate in 11:

[pgn][Event "Mate in 23"] [Site "Columbus, Ohio"] [Date "2024.01.24"] [Round "?"] [White "?"] [Black "?"] [Result "1-0"] [Time "20:11:50"] [TimeControl "0"] [SetUp "1"] [FEN "3R1nqb/B2n1prb/4pPp1/1p1kN1P1/1P2rP1K/2p5/2P1P3/7B w - - 0 1"] [Termination "normal"] [PlyCount "21"] [WhiteType "program"] [BlackType "program"] [Comment "bm #23; 00:00 @ C2/R0/K2/P1/X1;"] 1. Kg3 Kd6 2. Bb8+ Kd5 3. Kf2 Kd4 4. Nc6+ Kd5 5. Na5 Kd4 6. e3+ Kd5 7. Bg2 e5 8. Bc7 Ke6 9. Re8+ Kd5 10. Re7 Nxf6 11. Rxe5# 1-0 [/pgn]

https://www.yacpdb.org/#67687

Regards from the U.S.

This one was also marked as mate in 11 improved by SFMF9 in 2018

Code: Select all

3R1nqb/B2n1prb/4pPp1/1p1kN1P1/1P2rP1K/2p5/2P1P3/7B w - - bm #11; SFMF9;

Thanks for the information, I must have an old version of the ChestUCI database.

[sarona]

The updated ChestUCI_23102018.epd can be found at vondele's matetrack Github here https://github.com/vondele/matetrack/bl ... 102018.epd

[RobbyRob]

The updated ChestUCI_23102018.epd can be found at vondele's matetrack Github here https://github.com/vondele/matetrack/bl ... 102018.epd

That file is by now outdated, and still contains this 7men draw:

Code: Select all

1k4b1/3r3p/1K6/8/6p1/8/8/1Q6 w - - bm #32;

For the most up-to-date collection see https://github.com/vondele/matetrack/bl ... etrack.epd (observe though that currently a PR is open that shortens two more mates, one of them reported by this thread (thanks!)).

For those interested, all the PVs/mating lines that have been checked for correctness are at https://github.com/vondele/matetrack/bl ... rackpv.epd.