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

[acase]

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That file is by now outdated, and still contains this 7men draw: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

Thank you for the updated file.

[towforce]

I've missed something here: where does the data in the ChestUCI database come from, and how is it possible for it to contain suboptimal solutions?

[ImNotStockfish]

I've missed something here: where does the data in the ChestUCI database come from, and how is it possible for it to contain suboptimal solutions?

This is chest's website https://turbotm.de/~heiner/Chess/chest.html and this is chestuci's https://fhub.jimdofree.com/
It contains suboptimal solutions because most of them are not proven to be the shortest using the regular chest settings. They have some heuristics that limit what moves can be played and thus make mistakes.

[towforce]

I've missed something here: where does the data in the ChestUCI database come from, and how is it possible for it to contain suboptimal solutions?

This is chest's website https://turbotm.de/~heiner/Chess/chest.html and this is chestuci's https://fhub.jimdofree.com/
It contains suboptimal solutions because most of them are not proven to be the shortest using the regular chest settings. They have some heuristics that limit what moves can be played and thus make mistakes.

Thank you for that information. It is surprising to me that people would want a database of forced mates that aren't optimised.

[acase]

I've missed something here: where does the data in the ChestUCI database come from, and how is it possible for it to contain suboptimal solutions?

This is chest's website https://turbotm.de/~heiner/Chess/chest.html and this is chestuci's https://fhub.jimdofree.com/
It contains suboptimal solutions because most of them are not proven to be the shortest using the regular chest settings. They have some heuristics that limit what moves can be played and thus make mistakes.

Thank you for that information. It is surprising to me that people would want a database of forced mates that aren't optimised.

I think that is kind of the idea for me at least, we're trying to optimise the mates and it is an ever evolving project. Sometimes the intended solution of the composer isn't the shortest path to mate.

[towforce]

Andrew - thank you for that helpful and informative post.

[acase]

This Otto Blathy mate in 47 from the Chest Database looks like it can be shortened to mate in 44, also I should give some credit to Uri Blass here viewtopic.php?f=2&t=76302&p=879508&hili ... dc#p879508 for recognizing that this mate could be shortened, however he had it as a mate in 45.

As usual I may be full of crap, so it would be nice if someone could check my analysis:

[pgn][Event "Mate in 47 (or is it mate in 44?)"] [Site "Columbus, Ohio"] [Date "2024.02.17"] [Round "?"] [White "Otto Blathy"] [Black "?"] [Result "1-0"] [Time "16:20:00"] [TimeControl "0"] [SetUp "1"] [FEN "2b4b/Pr1p3P/qP1p2Q1/1R1n4/8/n6r/7P/k6K w - - 0 1"] [Termination "normal"] [PlyCount "87"] [WhiteType "human"] [BlackType "human"] [Comment "bm #47;"] 1. Qg1+ Ka2 2. Qf2+ Ka1 3. Qe1+ Ka2 4. Qd2+ Ka1 5. Qd1+ Ka2 6. Qxd5+ Ka1 7. Qd1+ Ka2 8. Qe2+ Ka1 9. Qf1+ Ka2 10. Qg2+ Ka1 11. Qg1+ Ka2 12. Qg8+ d5 13. Qxd5+ Ka1 14. Qd1+ Ka2 15. Qd2+ Ka1 16. Qe1+ Ka2 17. Qf2+ Ka1 18. Qg1+ Ka2 19. Qg8+ d5 20. Qxd5+ Ka1 21. Qd1+ Ka2 22. Qe2+ Ka1 23. Qe1+ Ka2 24. Qf2+ Ka1 25. Qg1+ Ka2 26. Qg8+ Rb3 (26. .. Be6 27. Qxe6+ Ka1 28. Qe1+ Ka2 29. Qf2+ Ka1 30. Qg1+ Ka2 31. Qg8+ Rb3 32. Qxb3+ Ka1 33. Qd1+ Ka2 34. Qe2+ Ka1 35. Rb1+ Kxb1 36. Qxa6 Rd7 37. Qf1+ Kb2 38. a8=Q Be5 39. Qc6 Kb3 40. Qxd7 Kc3 41. Qfd1 Kb4 42. Q1a4+ Kc3 43. Qxa3+ Kc4 44. Qdd3#) (26. .. Nc4 27. Qxc4+ Ka3 28. Qb4+ Ka2 29. Qd2+ Ka1 30. Ra5+ Kb1 31. Rxa6 Rd7 32. Qe1+ Kc2 33. Ra2+ Kd3 34. Qd2+ Ke4 35. a8=Q+ Bb7 36. Qxd7 Bxa8 37. Rxa8 Bd4 38. Qe6+ Kd3 39. Ra3+ Kc2 40. Qxh3 Kb2 41. Qd3 Kc1 42. Ra2 Bb2 43. Qe2 Kb1 44. Qxb2#) 27. Qxb3+ Ka1 28. Qd1+ Ka2 29. Qe2+ Ka1 30. Rb1+ Kxb1 31. Qxa6 Re7 32. Qxc8 Re1+ 33. Kg2 Nc2 34. Qxh8 Re2+ 35. Kf1 Re1+ 36. Kf2 Re3 37. a8=Q Rd3 38. Qh1+ Ka2 39. Qc1 Rf3+ 40. Kxf3 Kb3 41. Qhb2+ Kc4 42. Qcxc2+ Kd5 43. Qe4+ Kc5 44. Qbb4# 1-0 [/pgn]

[Ajedrecista]

Hello Andrew:

This Otto Blathy mate in 47 from the Chest Database looks like it can be shortened to mate in 44, also I should give some credit to Uri Blass here viewtopic.php?f=2&t=76302&p=879508&hili ... dc#p879508 for recognizing that this mate could be shortened, however he had it as a mate in 45.

As usual I may be full of crap, so it would be nice if someone could check my analysis:

[pgn][Event "Mate in 47 (or is it mate in 44?)"] [Site "Columbus, Ohio"] [Date "2024.02.17"] [Round "?"] [White "Otto Blathy"] [Black "?"] [Result "1-0"] [Time "16:20:00"] [TimeControl "0"] [SetUp "1"] [FEN "2b4b/Pr1p3P/qP1p2Q1/1R1n4/8/n6r/7P/k6K w - - 0 1"] [Termination "normal"] [PlyCount "87"] [WhiteType "human"] [BlackType "human"] [Comment "bm #47;"] 1. Qg1+ Ka2 2. Qf2+ Ka1 3. Qe1+ Ka2 4. Qd2+ Ka1 5. Qd1+ Ka2 6. Qxd5+ Ka1 7. Qd1+ Ka2 8. Qe2+ Ka1 9. Qf1+ Ka2 10. Qg2+ Ka1 11. Qg1+ Ka2 12. Qg8+ d5 13. Qxd5+ Ka1 14. Qd1+ Ka2 15. Qd2+ Ka1 16. Qe1+ Ka2 17. Qf2+ Ka1 18. Qg1+ Ka2 19. Qg8+ d5 20. Qxd5+ Ka1 21. Qd1+ Ka2 22. Qe2+ Ka1 23. Qe1+ Ka2 24. Qf2+ Ka1 25. Qg1+ Ka2 26. Qg8+ Rb3 (26. .. Be6 27. Qxe6+ Ka1 28. Qe1+ Ka2 29. Qf2+ Ka1 30. Qg1+ Ka2 31. Qg8+ Rb3 32. Qxb3+ Ka1 33. Qd1+ Ka2 34. Qe2+ Ka1 35. Rb1+ Kxb1 36. Qxa6 Rd7 37. Qf1+ Kb2 38. a8=Q Be5 39. Qc6 Kb3 40. Qxd7 Kc3 41. Qfd1 Kb4 42. Q1a4+ Kc3 43. Qxa3+ Kc4 44. Qdd3#) (26. .. Nc4 27. Qxc4+ Ka3 28. Qb4+ Ka2 29. Qd2+ Ka1 30. Ra5+ Kb1 31. Rxa6 Rd7 32. Qe1+ Kc2 33. Ra2+ Kd3 34. Qd2+ Ke4 35. a8=Q+ Bb7 36. Qxd7 Bxa8 37. Rxa8 Bd4 38. Qe6+ Kd3 39. Ra3+ Kc2 40. Qxh3 Kb2 41. Qd3 Kc1 42. Ra2 Bb2 43. Qe2 Kb1 44. Qxb2#) 27. Qxb3+ Ka1 28. Qd1+ Ka2 29. Qe2+ Ka1 30. Rb1+ Kxb1 31. Qxa6 Re7 32. Qxc8 Re1+ 33. Kg2 Nc2 34. Qxh8 Re2+ 35. Kf1 Re1+ 36. Kf2 Re3 37. a8=Q Rd3 38. Qh1+ Ka2 39. Qc1 Rf3+ 40. Kxf3 Kb3 41. Qhb2+ Kc4 42. Qcxc2+ Kd5 43. Qe4+ Kc5 44. Qbb4# 1-0 [/pgn]

What about 26.- ..., Rf7, as proposed by Uri? I could not improve the #45, for example:

26.- ..., Rf7; 27.- Qxf7+, Ka1; 28.- Qf1+, Ka2; 29.- Qf2+, Ka1; 30.- Qg1+, Ka2; 31.- Qg8+, Rb3; 32.- Qxb3+, Ka1; 33.- Qd1+, Ka2; 34.- Qd5+, Ka1.

Playing up to 34.- ..., Ka1 with SF 16, then let Chest 5.2 in normal search mode to solve the position:

Code: Select all

FEN: 2b4b/P6P/qP6/1R1Q4/8/n7/7P/k6K w - - 5 35

ChestUCI:
FEN: 2b4b/P6P/qP6/1R1Q4/8/n7/7P/k6K w - -   (7+5)
Stellungs-Analyse:  C0/R0/K1/P4/X22   W:6/39
Suche nach Matt in 13 ...  (Hash=512MB)
  11	11:44	 519.157.918	821.030	+M11	b6b7
  11	14:13	 578.022.298	821.500	+M11	a7a8Q
Suche abgeschlossen ...  (Zeit=1780.71s)
Matt in 11 gefunden !  (2 Lösungen in 29:40)
 11/11	29:45	1.465.371.465	822.913	+M11	a7a8Q Na3xb5 b6b7 Bc8xb7 Qd5xb7 Qa6xa8 Qb7xa8+ Ka1b1 Qa8xh8 Nb5d6 Qh8b8+ Nd6b5 Qb8xb5+ Kb1c2 Qb5a4+ Kc2d2 h7h8Q Kd2e2 Qh8d4 Ke2e1 Qa4d1+
 11/11	29:45	1.465.371.465	822.913	+M11	b6b7 Na3xb5 b7xc8Q Qa6xc8 a7a8Q+ Qc8xa8 Qd5xa8+ Ka1b1 Qa8xh8 Nb5d6 Qh8b8+ Nd6b5 Qb8xb5+ Kb1c2 Qb5a4+ Kc2d2 h7h8Q Kd2e2 Qh8d4 Ke2e1 Qa4d1+

A #44 would require something faster for white between moves 27 and 34 of the line given above.

Regards from Spain.

Ajedrecista.

[acase]

Hello Andrew:

This Otto Blathy mate in 47 from the Chest Database looks like it can be shortened to mate in 44, also I should give some credit to Uri Blass here viewtopic.php?f=2&t=76302&p=879508&hili ... dc#p879508 for recognizing that this mate could be shortened, however he had it as a mate in 45.

As usual I may be full of crap, so it would be nice if someone could check my analysis:

[pgn][Event "Mate in 47 (or is it mate in 44?)"] [Site "Columbus, Ohio"] [Date "2024.02.17"] [Round "?"] [White "Otto Blathy"] [Black "?"] [Result "1-0"] [Time "16:20:00"] [TimeControl "0"] [SetUp "1"] [FEN "2b4b/Pr1p3P/qP1p2Q1/1R1n4/8/n6r/7P/k6K w - - 0 1"] [Termination "normal"] [PlyCount "87"] [WhiteType "human"] [BlackType "human"] [Comment "bm #47;"] 1. Qg1+ Ka2 2. Qf2+ Ka1 3. Qe1+ Ka2 4. Qd2+ Ka1 5. Qd1+ Ka2 6. Qxd5+ Ka1 7. Qd1+ Ka2 8. Qe2+ Ka1 9. Qf1+ Ka2 10. Qg2+ Ka1 11. Qg1+ Ka2 12. Qg8+ d5 13. Qxd5+ Ka1 14. Qd1+ Ka2 15. Qd2+ Ka1 16. Qe1+ Ka2 17. Qf2+ Ka1 18. Qg1+ Ka2 19. Qg8+ d5 20. Qxd5+ Ka1 21. Qd1+ Ka2 22. Qe2+ Ka1 23. Qe1+ Ka2 24. Qf2+ Ka1 25. Qg1+ Ka2 26. Qg8+ Rb3 (26. .. Be6 27. Qxe6+ Ka1 28. Qe1+ Ka2 29. Qf2+ Ka1 30. Qg1+ Ka2 31. Qg8+ Rb3 32. Qxb3+ Ka1 33. Qd1+ Ka2 34. Qe2+ Ka1 35. Rb1+ Kxb1 36. Qxa6 Rd7 37. Qf1+ Kb2 38. a8=Q Be5 39. Qc6 Kb3 40. Qxd7 Kc3 41. Qfd1 Kb4 42. Q1a4+ Kc3 43. Qxa3+ Kc4 44. Qdd3#) (26. .. Nc4 27. Qxc4+ Ka3 28. Qb4+ Ka2 29. Qd2+ Ka1 30. Ra5+ Kb1 31. Rxa6 Rd7 32. Qe1+ Kc2 33. Ra2+ Kd3 34. Qd2+ Ke4 35. a8=Q+ Bb7 36. Qxd7 Bxa8 37. Rxa8 Bd4 38. Qe6+ Kd3 39. Ra3+ Kc2 40. Qxh3 Kb2 41. Qd3 Kc1 42. Ra2 Bb2 43. Qe2 Kb1 44. Qxb2#) 27. Qxb3+ Ka1 28. Qd1+ Ka2 29. Qe2+ Ka1 30. Rb1+ Kxb1 31. Qxa6 Re7 32. Qxc8 Re1+ 33. Kg2 Nc2 34. Qxh8 Re2+ 35. Kf1 Re1+ 36. Kf2 Re3 37. a8=Q Rd3 38. Qh1+ Ka2 39. Qc1 Rf3+ 40. Kxf3 Kb3 41. Qhb2+ Kc4 42. Qcxc2+ Kd5 43. Qe4+ Kc5 44. Qbb4# 1-0 [/pgn]

What about 26.- ..., Rf7, as proposed by Uri? I could not improve the #45, for example:

26.- ..., Rf7; 27.- Qxf7+, Ka1; 28.- Qf1+, Ka2; 29.- Qf2+, Ka1; 30.- Qg1+, Ka2; 31.- Qg8+, Rb3; 32.- Qxb3+, Ka1; 33.- Qd1+, Ka2; 34.- Qd5+, Ka1.

Playing up to 34.- ..., Ka1 with SF 16, then let Chest 5.2 in normal search mode to solve the position:

Code: Select all

FEN: 2b4b/P6P/qP6/1R1Q4/8/n7/7P/k6K w - - 5 35

ChestUCI:
FEN: 2b4b/P6P/qP6/1R1Q4/8/n7/7P/k6K w - -   (7+5)
Stellungs-Analyse:  C0/R0/K1/P4/X22   W:6/39
Suche nach Matt in 13 ...  (Hash=512MB)
  11	11:44	 519.157.918	821.030	+M11	b6b7
  11	14:13	 578.022.298	821.500	+M11	a7a8Q
Suche abgeschlossen ...  (Zeit=1780.71s)
Matt in 11 gefunden !  (2 Lösungen in 29:40)
 11/11	29:45	1.465.371.465	822.913	+M11	a7a8Q Na3xb5 b6b7 Bc8xb7 Qd5xb7 Qa6xa8 Qb7xa8+ Ka1b1 Qa8xh8 Nb5d6 Qh8b8+ Nd6b5 Qb8xb5+ Kb1c2 Qb5a4+ Kc2d2 h7h8Q Kd2e2 Qh8d4 Ke2e1 Qa4d1+
 11/11	29:45	1.465.371.465	822.913	+M11	b6b7 Na3xb5 b7xc8Q Qa6xc8 a7a8Q+ Qc8xa8 Qd5xa8+ Ka1b1 Qa8xh8 Nb5d6 Qh8b8+ Nd6b5 Qb8xb5+ Kb1c2 Qb5a4+ Kc2d2 h7h8Q Kd2e2 Qh8d4 Ke2e1 Qa4d1+

A #44 would require something faster for white between moves 27 and 34 of the line given above.

Regards from Spain.

Ajedrecista.

Hi Jesus,

You're right, I thought I was possibly missing something there and the silly thing is that it was in the post by Uri that I quoted . Thanks for helping me see the light so to speak.

[MOBMAT]

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]

Houdini 603, the Houdidit version using Nalimov ETB found four solutions at M15

Code: Select all

 53/53	03:41	 4,677,869k	21,097k	+M15	1.Qg7 Ka6 2.Qxh7 g5 3.Qg7 Ka7 4.Qxg5 c5 5.Qxh4 b5 6.Qf2 Kb6 7.h4 Kc6 8.h5 c4 9.h6 cxb3 10.h7 b2 11.Qxb2 b3 12.h8Q b4 13.Qbd4 b2 14.Qe8+ Kc7 15.Qc5+
 53/53	03:41	 4,677,869k	21,097k	+M15	1.Qh8 Ka6 2.Qxh7 g5 3.Qg7 Ka7 4.Qxg5 c5 5.Qxh4 b5 6.Qf2 Kb6 7.h4 Kc6 8.h5 c4 9.h6 cxb3 10.h7 b2 11.Qxb2 b3 12.h8Q b4 13.Qbd4 b2 14.Qe8+ Kc7 15.Qc5+
 53/53	03:41	 4,677,869k	21,097k	+M15	1.Qe1 Ka6 2.Qxh4 h5 3.Qf6 Ka7 4.h4 c5 5.Qxg6 c4 6.Qxh5 cxb3 7.Qe5 b5 8.h5 b6 9.h6 Kb7 10.h7 b2 11.Qxb2 b3 12.h8Q b4 13.Qbd4 Ka6 14.Qa8+ Kb5 15.Qdd5+
 53/53	03:41	 4,677,869k	21,097k	+M15	1.Qd4 Ka6 2.Qxh4 h5 3.Qf6 Ka7 4.h4 c5 5.Qxg6 c4 6.Qxh5 cxb3 7.Qe5 b5 8.h5 b6 9.h6 Kb7 10.h7 b2 11.Qxb2 b3 12.h8Q b4 13.Qbd4 Ka6 14.Qa8+ Kb5 15.Qdd5+