Timeline for Solvable studies that computers fail to crack
Current License: CC BY-SA 4.0
13 events
| when toggle format | what | by | license | comment | |
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| Feb 28, 2019 at 12:08 | vote | accept | user929304 | ||
| Apr 1, 2020 at 19:16 | |||||
| Feb 27, 2019 at 23:29 | comment | added | konsolas | It does not find your suggested line, but engines do tend to prune other lines very aggressively after they find a forced mate, however long, as it is a guaranteed win, even if shorter mating lines are available. Very interesting puzzle nonetheless. | |
| Feb 27, 2019 at 23:19 | comment | added | Ellie |
Alright, so that's essentially a mate in 38 starting from the initial position. But does it see the mate in 22 which is the 3.Ra1...6.e8=B.. line? 1. Rb1 a5 2. Rd1 a6 3. Ra1 d5 4. e6 d4 5. e7 d3 6. e8=B d2 7. Bh5 d1=Q 8. Bxd1 Nh3 9. Bc2+ Ng1 10. Bb1 Nh3 11. Be4+ Ng1 12. Ra2 Nf3 13. Bxf3 Kg1 14. Rxg2+ Kf1 15. Rxh2 Kg1 16. Re2 Kf1 17. Ke7 Kg1 18. Ke6 Kf1 19. Kf5 Kg1 20. Kg4 Kf1 21. Kg3 Kg1 22. Re1#
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| Feb 27, 2019 at 23:06 | comment | added | konsolas |
OK, Kf7 is a win with a mate in 36, according to Houdini. This is the PV: 1.Kf7 { #36/60 } 1...d5 2.e6 d4 3.e7 d3 4.e8=Q d2 5.Rxd2 Nf3 6.Rd3 g1=Q 7.Rxf3 Qa7+ 8.Ke6 Qb6+ 9.Kf5 Qb1+ 10.Kg5 Qc1+ 11.Kh5 Qd1 12.Qe4 Kg1 13.Qg4+ Kh1 14.Kh4 Qd8+ 15.Kg3 Qd4 16.Qh5 Qg7+ 17.Kh3 Qd7+ 18.Qf5 Qxf5+ 19.Rxf5 Kg1 20.Rg5+ Kh1 21.Kg3 Kg1 22.Re5 Kf1 23.Kxh2 Kf2 24.Re6 Kf3 25.Rxa6 Ke2 26.Rxa5 Kd2 27.Rh5 Kd3 28.a5 Ke4 29.a6 Kf4 30.Ra5 Ke4 31.a7 Kd3 32.a8=Q Kc2 33.Rd5 Kb1 34.Qc6 Ka1 35.Rb5 Ka2 36.Qa6# *
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| Feb 27, 2019 at 22:41 | comment | added | konsolas |
It's possible that Kf7 is a win as well.
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| Feb 27, 2019 at 22:37 | comment | added | Ellie |
@konsolas haha great then it doesn't see the key line (3.Ra1 ...6.e8=B...) ;) but maybe after a sufficiently long time... anyhow I checked these things long time ago and at the time engines proved hopeless in finding this short-forced winning line.
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| Feb 27, 2019 at 22:33 | comment | added | konsolas |
Analysing from 2. ... a3, with no further guidance and an empty hash, Houdini reports a mate in 120, best move Kf7. It's currently constructing the PV, but it looks unlikely to finish any time soon.
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| Feb 27, 2019 at 22:22 | comment | added | konsolas |
Here is Houdini's mating line from the end of the 9. Rxf3: 9...Qa7+ { #31/48 } 10.Ke6 Qb6+ 11.Kf5 Qb1+ 12.Kg5 Qc1+ 13.Kh5 Qb1 14.Qe5 Qd1 15.Qe4 Kg2 16.Qg4+ Kh1 17.Kh4 Qd8+ 18.Kg3 Qd4 19.Qh5 Qg7+ 20.Kh3 Qd7+ 21.Qf5 Qxf5+ 22.Rxf5 Kg1 23.Rg5+ Kh1 24.Kg3 Kg1 25.Re5 Kf1 26.Kxh2 Kf2 27.Re6 Kf3 28.Rxa6 Ke4 29.Rxa5 Kf3 30.Rb5 Ke3 31.a5 Kd3 32.Kg3 Kd2 33.a6 Kd3 34.Rg5 Kc4 35.a7 Kd4 36.a8=Q Kc3 37.Qc6+ Kd2 38.Rd5+ Ke2 39.Qe8+ Kf1 40.Rd1# * I still need to check the rest of the Kf7 line
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| Feb 27, 2019 at 22:16 | comment | added | Ellie |
@konsolas right so I guess the naive tablebase look up by neglecting the a-file pawns doesn't really work here. I analysed these lines long time ago, maybe the 3.Kf7 line is still a draw and I may have misplayed it somewhere along that line, I'm curious whether Houdini sees the win already from 3.Kf7? On the other hand, does it at all see the bishop promotion solution without you guiding it towards the Ra1 line?
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| Feb 27, 2019 at 21:56 | comment | added | konsolas |
Interestingly, Houdini reports a mate in 31 for the 3.Kf7....9.Rxf3 line. Is there a strategy black can follow in that position that guarantees a draw?
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| Feb 27, 2019 at 16:19 | comment | added | user929304 | Wow! this is nuts...I'm trying the position using the cloud SF on lichess, and it completely fails to see the winning line you show and keeps saying +50 for the lines that are fortress! Neat!! | |
| Feb 27, 2019 at 16:16 | comment | added | Ellie |
A note for the line with 3.Kf7....9.Rxf3, you can check that it's a fortress by removing the pawns on the a-file and asking the tablebase (with black to move), it will show you the draw. Otherwise keep trying with an engine and you'll see none of the lines lead to a conversion for white.
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| Feb 27, 2019 at 15:41 | history | answered | Ellie | CC BY-SA 4.0 |