8 hard positions from the Chest database

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peter
Posts: 3338
Joined: Sat Feb 16, 2008 7:38 am
Full name: Peter Martan

Re: 8 hard positions from the Chest database

Post by peter »

Dann Corbit wrote: ↑Fri Mar 29, 2024 7:39 pm These are the only 8 positions for which I have not found a checkmate solution:
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abcdefgh

2r1b1Q1/6p1/2P5/5P2/1p2K3/pPp5/n2P4/1B2k3 w - - acd 44; bm Kf4; ce 630; c2 "#23;"; pm Kf4; pv Kf4; id "ChestDB.06301";
Having many positions in one thread always makes it difficult to follow all the postings to different single ones of them.
Haven't seen anybody dealing with this first one nearer, couldn't find another one source but Chest- database so far neither and don't come even near to DTM 23 with some Forward- Backward with Huntsman, Chest and Gustav too seem not to stand a chance with given #23 and the very starting position, tried automatic parameters so far only.

Here's the shortest line to mate I got so far, backward to about 15th move DTM- output can be kept in hash of 32G and 30 threads

Peter.
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acase
Posts: 994
Joined: Wed Mar 15, 2006 1:14 am
Location: Columbus, Ohio USA
Full name: Andrew R Case

Re: 8 hard positions from the Chest database

Post by acase »

The best I could come up with for the mate in 64 was a mate in 66, once again there might be some place where I messed up at but at least we know how it works:

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peter
Posts: 3338
Joined: Sat Feb 16, 2008 7:38 am
Full name: Peter Martan

Re: 8 hard positions from the Chest database

Post by peter »

peter wrote: ↑Sat Mar 30, 2024 12:39 pm
Dann Corbit wrote: ↑Fri Mar 29, 2024 7:39 pm These are the only 8 positions for which I have not found a checkmate solution:
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abcdefgh

2r1b1Q1/6p1/2P5/5P2/1p2K3/pPp5/n2P4/1B2k3 w - - acd 44; bm Kf4; ce 630; c2 "#23;"; pm Kf4; pv Kf4; id "ChestDB.06301";
Maybe not only DTM but bm could be wrong too?
Sting favors 1.Qe6, Huntsman get's this output with some Forward- Backward from and to these first 5 moves

2r1b1Q1/6p1/2P5/5P2/1p2K3/pPp5/n2P4/1B2k3 w - - 0 1
1. Qe6 Bf7 2. Qxc8 cxd2 3. Bc2 Nc3+ 4. Ke3 d1=Q 5. Bxd1 Kxd1

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abcdefgh

2Q5/5bp1/2P5/5P2/1p6/pPn1K3/8/3k4 w - - 0 1

Analysis by The Huntsman 1:

6.c7 Kc2 7.Qb7 a2 8.Qa6 Kb2 9.c8Q a1Q 10.Qxa1+ Kxa1 11.Qf8 Bh5 12.Kd3 Kb2 13.Qxb4 Na2 14.Qb7 Nc1+ 15.Kd2 Nxb3+ 16.Kd3 Be2+ 17.Kxe2 Kc3 18.Qxg7+ Kc4 19.Ke3 Nc5 20.Qd4+ Kb5 21.Qd5 Kb6 22.f6 Na6 23.f7 Nc7 24.Qd6+ Kb5 25.Qxc7 Ka4 26.f8Q Kb3 27.Qfb8+ Ka3 28.Qca7#
Depth: 63/46 00:00:00 13858kN
Peter.
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peter
Posts: 3338
Joined: Sat Feb 16, 2008 7:38 am
Full name: Peter Martan

Re: 8 hard positions from the Chest database

Post by peter »

peter wrote: ↑Sat Mar 30, 2024 3:08 pm
peter wrote: ↑Sat Mar 30, 2024 12:39 pm
Dann Corbit wrote: ↑Fri Mar 29, 2024 7:39 pm These are the only 8 positions for which I have not found a checkmate solution:
8 
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1 
abcdefgh

2r1b1Q1/6p1/2P5/5P2/1p2K3/pPp5/n2P4/1B2k3 w - - acd 44; bm Kf4; ce 630; c2 "#23;"; pm Kf4; pv Kf4; id "ChestDB.06301";
Maybe not only DTM but bm could be wrong too?
Sting favors 1.Qe6, Huntsman get's this output with some Forward- Backward from and to these first 5 moves

2r1b1Q1/6p1/2P5/5P2/1p2K3/pPp5/n2P4/1B2k3 w - - 0 1
1. Qe6 Bf7 2. Qxc8 cxd2 3. Bc2 Nc3+ 4. Ke3 d1=Q 5. Bxd1 Kxd1

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abcdefgh

2Q5/5bp1/2P5/5P2/1p6/pPn1K3/8/3k4 w - - 0 1

Analysis by The Huntsman 1:

6.c7 Kc2 7.Qb7 a2 8.Qa6 Kb2 9.c8Q a1Q 10.Qxa1+ Kxa1 11.Qf8 Bh5 12.Kd3 Kb2 13.Qxb4 Na2 14.Qb7 Nc1+ 15.Kd2 Nxb3+ 16.Kd3 Be2+ 17.Kxe2 Kc3 18.Qxg7+ Kc4 19.Ke3 Nc5 20.Qd4+ Kb5 21.Qd5 Kb6 22.f6 Na6 23.f7 Nc7 24.Qd6+ Kb5 25.Qxc7 Ka4 26.f8Q Kb3 27.Qfb8+ Ka3 28.Qca7#
Depth: 63/46 00:00:00 13858kN
After 1.Qe6 Bf7:

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abcdefgh

2r5/5bp1/2P1Q3/5P2/1p2K3/pPp5/n2P4/1B2k3 w - - 0 1

Analysis by The Huntsman 1:

2.Qxc8 cxd2 3.Bc2 Nc3+ 4.Ke3 a2 5.Qa6 Be8 6.c7 Bd7 7.Qa8 d1N+ 8.Bxd1 Nxd1+ 9.Kd4 Nc3 10.Kc5 Kd2 11.Kxb4 Bxf5 12.Qg2+ Ne2 13.Qxg7 Bc8 14.Qb2+ Ke3 15.Qxa2 Bg4 16.Qa6 Ng3 17.Kc5 Ne2 18.c8Q Bxc8 19.Qxc8 Kf4 20.Kc4 Kf3 21.Qf5+ Ke3 22.Qg5+ Kf3 23.b4 Ng3 24.b5 Ne4 25.Qd5 Ke3 26.Qd4+ Kf3 27.b6 Ng3 28.Qd3+ Kg4 29.b7 Kh4 30.b8Q Nh5 31.Qe4+ Kh3 32.Qf3+ Kh4 33.Qh2+ Kg5 34.Qhxh5#
Depth: 60/66 00:01:00 2992MN

Output with even shorter DTM I get after 1...Bxc6, 1...Rxc6, 1...Kd1, 1...Bh5 but to keep all these and other alternatives at 1st move of Black's in 32G hash in reasonable hardware- time together with 1st move of White's I gave up trying. One more full move backward to original starting position I'm leaving for good, regards
Last edited by peter on Sat Mar 30, 2024 8:37 pm, edited 2 times in total.
Peter.
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Dann Corbit
Posts: 12748
Joined: Wed Mar 08, 2006 8:57 pm
Location: Redmond, WA USA

Re: 8 hard positions from the Chest database

Post by Dann Corbit »

I would not be surprised if there were many errors.
Thanks for all the efforts.
For the first two problems addressed, I analyzed the following positions, mostly to fill the hash:

Code: Select all

3k4/KP2p3/2p1P3/2P5/2p3p1/2Pp2Pp/3P3P/8 w - - acd 999; bm b8=Q#; ce 32766; dm 1; pm b8=Q#; 
Q1Q5/4p3/1k2P3/6p1/2P3Pp/7P/1p1K4/8 w - - acd 80; bm Qaa6+; ce 32766; dm 1; pm Qaa6+; 
8/1Pk1p3/K1p1P3/2P5/2p3p1/2Pp2Pp/3P3P/8 w - - acd 999; bm Ka7; ce 32764; dm 2; pm Ka7; c9 "HHdbVI.1156970.063a.57979"; 
Q7/2P1p3/1k2P3/6p1/2P3Pp/1p5P/3K4/8 w - - acd 80; bm c8=Q; ce 32764; dm 2; pm c8=Q; 
1k6/4p3/KPp1P3/2P5/2p3p1/2Pp2Pp/3P3P/8 w - - acd 999; bm b7; ce 32762; dm 3; pm b7; c9 "HHdbVI.1156968.062a.57979"; 
8/PkP1p3/1P2P3/6p1/2P3Pp/1p5P/3K4/8 w - - acd 80; bm c8=Q+; ce 32762; dm 3; pm c8=Q+; 
k7/4p3/1Pp1P3/K1P5/2p3p1/2Pp2Pp/3P3P/8 w - - acd 999; bm Ka6; ce 32760; dm 4; pm Ka6; c9 "HHdbVI.1156966.061a.57979"; 
k7/P3p3/1PP1P3/6p1/2P3Pp/1p5P/3K4/8 w - - acd 80; bm c7; ce 32760; dm 4; pm c7; 
8/Pk2p3/1Pp1P3/K1P5/2p3p1/2Pp2Pp/3P3P/8 w - - acd 999; bm a8=Q+ a8=R; ce 32758; dm 5; pm a8=Q+ a8=R; c9 "HHdbVI.1156964.060a.57979"; 
k7/P3p3/1PP1P3/6p1/1p4Pp/2P4P/3K4/8 w - - acd 80; bm c4; ce 32758; dm 5; pm c4; 
k7/P3p3/1P2P3/1pP3p1/6Pp/2P4P/3K4/8 w - - acd 80; bm c6; ce 32756; dm 6; pm c6; 
k7/P3p3/1Pp1P3/2P5/1Kp3p1/2Pp2Pp/3P3P/8 w - - acd 999; bm Ka5; ce 32756; dm 6; pm Ka5; c9 "HHdbVI.1156962.059a.57979"; 
8/Pk2p3/1Pp1P3/K1P5/1pp3p1/2Pp2Pp/3P3P/8 w - - acd 999; bm Kxb4; ce 32754; dm 7; pm Kxb4; c9 "HHdbVI.1156960.058a.57979"; 
k7/P3p3/1Pp1P3/1PP3p1/6Pp/2P4P/3p4/2K5 w - - acd 80; bm Kxd2; ce 32754; dm 7; pm Kxd2; 
8/Pk2p3/1Pp1P3/1pP5/1Kp3p1/2Pp2Pp/3P3P/8 w - - acd 999; bm Ka5; ce 32752; dm 8; pm Ka5; c9 "HHdbVI.1156958.057a.57979"; 
k7/P3p3/1Pp1P3/2P3p1/1P4Pp/2Pp3P/8/2K5 w - - acd 80; bm b5; ce 32752; dm 8; pm b5; 
8/Pk2p3/1Pp1P3/2P3p1/1P4Pp/2pp3P/3P4/2K5 w - - acd 80; bm dxc3; ce 32750; dm 9; pm dxc3; 
k7/P3p3/1Pp1P3/1pP5/2p3p1/K1Pp2Pp/3P3P/8 w - - acd 999; bm Kb4; ce 32750; dm 9; pm Kb4; c9 "HHdbVI.1156956.056a.57979"; 
8/Pk2p3/1Pp1P3/1pP5/2p3p1/2Pp2Pp/1K1P3P/8 w - - acd 999; bm Ka3; ce 32748; dm 10; pm Ka3; c9 "HHdbVI.1156954.055a.57979"; 
8/Pk2p3/1Pp1P3/2P3p1/1pp3Pp/2Pp3P/3P4/2K5 w - - acd 80; bm cxb4; ce 32748; dm 10; pm cxb4; 
k7/P3p3/1Pp1P3/1pP5/2p3p1/2Pp2Pp/K2P3P/8 w - - acd 999; bm Kb2; ce 32746; dm 11; pm Kb2; c9 "HHdbVI.1156952.054a.57979"; 
8/Pk2p3/1Pp1P3/1pP3p1/2p3Pp/2Pp3P/3P4/1K6 w - - acd 80; bm Kc1; ce 32744; dm 12; pm Kc1; 
k7/P3p3/1Pp1P1p1/2P3p1/1P5p/2pp1P1P/3P4/1K6 w - - acd 80; bm Kc1; ce 32744; dm 12; pm Kc1; 
k7/P3p3/1Pp1P1p1/2P3p1/1pp4p/2Pp1P1P/3P4/1K6 w - - acd 80; bm cxb4; ce 32742; dm 13; pm cxb4; 
k7/P3p3/1Pp1P3/1pP3p1/2p3Pp/2Pp3P/1K1P4/8 w - - acd 80; bm Kb1; ce 32742; dm 13; pm Kb1; 
8/Pk2p3/1Pp1P3/1pP3p1/2p3Pp/K1Pp3P/3P4/8 w - - acd 80; bm Kb2; ce 32740; dm 14; pm Kb2; 
8/Pk2p3/1Pp1P3/1pP5/2p3p1/K1Pp2Pp/3P3P/8 w - - acd 999; bm Ka2 Kb2; ce 32740; dm 14; pm Ka2 Kb2; c9 "HHdbVI.1156950.053a.57979"; 
k7/P3p3/1Pp1P3/1pP3p1/1Kp3Pp/2Pp3P/3P4/8 w - - acd 80; bm Ka3; ce 32738; dm 15; pm Ka3; 
k7/P3p3/1Pp1P3/1pP5/1Kp3p1/2Pp2Pp/3P3P/8 w - - acd 999; bm Ka3; ce 32738; dm 15; pm Ka3; c9 "HHdbVI.1156948.052a.57979"; 
8/Pk2p3/1Pp1P3/KpP3p1/2p3Pp/2Pp3P/3P4/8 w - - acd 80; bm Kb4; ce 32736; dm 16; pm Kb4; 
8/Pk2p3/1Pp1P3/KpP5/2p3p1/2Pp2Pp/3P3P/8 w - - acd 999; bm Kb4; ce 32736; dm 16; pm Kb4; c9 "HHdbVI.1156946.051a.57979"; 
8/Pk2p3/1Pp1P1p1/KpP5/2p3pp/2Pp1P1P/3P4/8 w - - acd 80; bm fxg4; ce 32734; dm 17; pm fxg4; 
8/Pk2p3/1Pp1P3/KpP3p1/2p5/2Pp2pp/3P1P1P/8 w - - acd 999; bm fxg3; ce 32734; dm 17; pm fxg3; c9 "HHdbVI.1156944.050a.57979"; 
8/Pk2p3/1Pp1P1p1/1pP3p1/1Kp4p/2Pp1P1P/3P4/8 w - - acd 80; bm Ka5; ce 32732; dm 18; pm Ka5; 
8/Pk2p3/1Pp1P3/1pP3p1/1Kp3p1/2Pp3p/3P1P1P/8 w - - acd 999; bm Ka5; ce 32732; dm 18; pm Ka5; c9 "HHdbVI.1156942.049a.57979"; 
k7/P3p3/1Pp1P1p1/1pP3p1/2p4p/K1Pp1P1P/3P4/8 w - - acd 80; bm Kb4; ce 32730; dm 19; pm Kb4; 
k7/P3p3/1Pp1P3/1pP3p1/2p3p1/K1Pp3p/3P1P1P/8 w - - acd 999; bm Kb4; ce 32730; dm 19; pm Kb4; c9 "HHdbVI.1156940.048a.57979"; 
8/Pk2p3/1Pp1P1p1/1pP3p1/2p4p/2Pp1P1P/1K1P4/8 w - - acd 80; bm Ka3; ce 32728; dm 20; pm Ka3; 
8/Pk2p3/1Pp1P3/1pP3p1/2p3p1/2Pp3p/1K1P1P1P/8 w - - acd 999; bm Ka3; ce 32728; dm 20; pm Ka3; c9 "HHdbVI.1156938.047a.57979"; 
k7/P3p3/1Pp1P1p1/1pP3p1/2p4p/2Pp1P1P/K2P4/8 w - - acd 80; bm Kb2; ce 32726; dm 21; pm Kb2; 
k7/P3p3/1Pp1P3/1pP3p1/2p3p1/2Pp3p/K2P1P1P/8 w - - acd 999; bm Kb2; ce 32726; dm 21; pm Kb2; c9 "HHdbVI.1156936.046a.57979"; 
8/Pk2p3/1Pp1P1p1/1pP3p1/2p4p/K1Pp1P1P/3P4/8 w - - acd 80; bm Ka2; ce 32724; dm 22; pm Ka2; 
8/Pk2p3/1Pp1P3/1pP3p1/2p3p1/K1Pp3p/3P1P1P/8 w - - acd 70; bm Ka2; ce 32724; dm 22; pm Ka2; c9 "HHdbVI.1156934.045a.57979"; 
k7/P3p3/1Pp1P1p1/1pP3p1/1Kp4p/2Pp1P1P/3P4/8 w - - acd 80; bm Ka3; ce 32722; dm 23; pm Ka3; 
k7/P3p3/1Pp1P1p1/1pP3p1/2p4p/2Pp1P1P/1K1P4/8 w - - acd 80; bm Kc1; ce 32722; dm 23; pm Kc1; 
k7/P3p3/1Pp1P3/1pP3p1/1Kp3p1/2Pp3p/3P1P1P/8 w - - acd 70; bm Ka3; ce 32722; dm 23; pm Ka3; c9 "HHdbVI.1156932.044a.57979"; 
8/Pk2p3/1Pp1P1p1/KpP3p1/2p4p/2Pp1P1P/3P4/8 w - - acd 80; bm Kb4; ce 32720; dm 24; pm Kb4; 
8/Pk2p3/1Pp1P3/KpP3p1/2p3p1/2Pp3p/3P1P1P/8 w - - acd 70; bm Kb4; ce 32720; dm 24; pm Kb4; c9 "HHdbVI.1156930.043a.57979"; 
8/Pk2p1p1/1Pp1P3/1pP3p1/1Kp4p/2Pp1P1P/3P4/8 w - - acd 80; bm Ka5; ce 32718; dm 25; pm Ka5; 
8/Pk2p3/1Pp1P1p1/1pP3pp/1Kp5/2Pp1P1P/3P4/8 w - - acd 80; bm Ka5; ce 32718; dm 25; pm Ka5; 
8/Pk2p3/1Pp1P3/1pP3p1/1Kp3pp/2Pp4/3P1P1P/8 w - - acd 70; bm Ka5; ce 32718; dm 25; pm Ka5; c9 "HHdbVI.1156928.042a.57979"; 
1Rn4k/n1p5/p2p1N1P/2bP3p/8/p1p1P2p/P1P1PP1P/6K1 w - - acd 70; bm Rb1; ce 32716; dm 26; pm Rb1; 
k7/P3p1p1/1Pp1P3/1pP3p1/2p4p/K1Pp1P1P/3P4/8 w - - acd 80; bm Kb4; ce 32716; dm 26; pm Kb4; 
k7/P3p3/1Pp1P1p1/1pP3pp/2p5/K1Pp1P1P/3P4/8 w - - acd 80; bm Kb4; ce 32716; dm 26; pm Kb4; 
k7/P3p3/1Pp1P3/1pP3p1/2p3pp/K1Pp4/3P1P1P/8 w - - acd 70; bm Kb4; ce 32716; dm 26; pm Kb4; c9 "HHdbVI.1156926.041a.57979"; 
1Rn4k/n1p5/pb1p1N1P/3P3p/8/p1p1P2p/P1P1PP1P/7K w - - acd 70; bm Kg1; ce 32714; dm 27; pm Kg1; 
8/Pk2p1p1/1Pp1P3/1pP3p1/2p4p/2Pp1P1P/1K1P4/8 w - - acd 80; bm Ka3; ce 32714; dm 27; pm Ka3; 
8/Pk2p3/1Pp1P1p1/1pP3pp/2p5/2Pp1P1P/1K1P4/8 w - - acd 80; bm Ka3; ce 32714; dm 27; pm Ka3; 
8/Pk2p3/1Pp1P3/1pP3p1/2p3pp/2Pp4/1K1P1P1P/8 w - - acd 70; bm Ka3; ce 32714; dm 27; pm Ka3; c9 "HHdbVI.1156924.040a.57979"; 
k7/P3p1p1/1Pp1P3/1pP3p1/2p4p/2Pp1P1P/3P4/1K6 w - - acd 80; bm Kb2; ce 32712; dm 28; pm Kb2; 
k7/P3p3/1Pp1P1p1/1pP3pp/2p5/2Pp1P1P/K2P4/8 w - - acd 80; bm Kb2; ce 32712; dm 28; pm Kb2; 
k7/P3p3/1Pp1P3/1pP3p1/2p3pp/2Pp4/K2P1P1P/8 w - - acd 60; bm Kb2; ce 32712; dm 28; pm Kb2; c9 "HHdbVI.1156922.039a.57979"; 
R1n4k/n1p5/pb1p1N1P/3P3p/7p/p1p1P3/P1P1PP1P/7K w - - acd 70; bm Rb8; ce 32712; c7 "No. 309494 (id: P1402334) Rotenberg, Jacques; Loustau, Jean-Marc source 1: Phenix, 1993-1994 stipulation: #34 solution: 1.Tb8! h3 2.Kg1 Lc5 3.Kf1 Lb6 4.Ke1 Lc5 5.Kd1 Lb6 6.Kc1 Lc5 7.Kb1 Lb6 8.Ka1 h4 9.Kb1 Lc5 10.Kc1 Lb6 11.Kd1 Lc5 12.Ke1 Lb6 13.Kf1 Lc5 14.Kg1 Lb6 15.Kh1 a5 16.Kg1 Lc5 17.Kf1 Lb6 18.Ke1 Lc5 19.Kd1 Lb6 20.Kc1 Lc5 21.Kb1 Lb6 22.Ka1 a4 23.Kb1 Lc5 24.Kc1 Lb6 25.Kd1 Lc5 26.Ke1 Lb6 27.Kf1 Lc5 28.Kg1 Lb6 29.Kh1 Lc5! 30.Tb1 Ld4 31.exd4 Se7 32.Tg1 Sg6 33.Txg6 ...34.Tg8#"; dm 28; pm Rb8; id "ChestDB.06430"; 
8/Pk2p1p1/1Pp1P3/1pP3p1/2p4p/2Pp1P1P/3P4/2K5 w - - acd 80; bm Kb1; ce 32710; dm 29; pm Kb1; 
8/Pk2p1p1/1Pp1P3/1pP3p1/2p4p/K1Pp1P1P/3P4/8 w - - acd 80; bm Ka2; ce 32710; dm 29; pm Ka2; 
8/Pk2p3/1Pp1P1p1/1pP3pp/2p5/K1Pp1P1P/3P4/8 w - - acd 80; bm Ka2; ce 32710; dm 29; pm Ka2; 
8/Pk2p3/1Pp1P3/1pP3p1/2p3pp/K1Pp4/3P1P1P/8 w - - acd 59; bm Ka2; ce 32710; dm 29; pm Ka2; c9 "HHdbVI.1156920.038a.57979"; 
k7/P3p1p1/1Pp1P3/1pP3p1/1Kp4p/2Pp1P1P/3P4/8 w - - acd 80; bm Ka3; ce 32708; dm 30; pm Ka3; 
k7/P3p1p1/1Pp1P3/1pP3p1/2p4p/2Pp1P1P/1K1P4/8 w - - acd 80; bm Kb1; ce 32708; dm 30; pm Kb1; 
k7/P3p3/1Pp1P1p1/1pP3pp/1Kp5/2Pp1P1P/3P4/8 w - - acd 80; bm Ka3; ce 32708; dm 30; pm Ka3; 
k7/P3p3/1Pp1P3/1pP3p1/1Kp3pp/2Pp4/3P1P1P/8 w - - acd 61; bm Ka3; ce 32708; dm 30; pm Ka3; c9 "HHdbVI.1156918.037a.57979"; 
8/Pk2p1p1/1Pp1P3/KpP3p1/2p4p/2Pp1P1P/3P4/8 w - - acd 80; bm Kb4; ce 32706; dm 31; pm Kb4; 
8/Pk2p3/1Pp1P1p1/KpP3pp/2p5/2Pp1P1P/3P4/8 w - - acd 80; bm Kb4; ce 32706; dm 31; pm Kb4; 
8/Pk2p3/1Pp1P3/KpP3p1/2p3pp/2Pp4/3P1P1P/8 w - - acd 63; bm Kb4; ce 32706; dm 31; pm Kb4; c9 "HHdbVI.1156916.036a.57979"; 
8/Pk2p1p1/1Pp1P3/1pP3pp/1Kp5/2Pp1P1P/3P4/8 w - - acd 80; bm Ka5; ce 32704; dm 32; pm Ka5; 
8/Pk2p1p1/1Pp1P3/KpP3pp/2p5/2Pp1P2/3P3P/8 w - - acd 80; bm h3; ce 32704; dm 32; pm h3; 
8/Pk2p3/1Pp1P3/1pP3pp/1Kp3p1/2Pp4/3P1P1P/8 w - - acd 65; bm Ka5; ce 32704; dm 32; pm Ka5; 
8/Pk2p1p1/1Pp1P2p/1pP3p1/1Kp5/2Pp1P2/3P3P/8 w - - acd 80; bm Ka5; ce 32702; dm 33; pm Ka5; 
k7/P3p1p1/1Pp1P3/1pP3pp/2p5/K1Pp1P1P/3P4/8 w - - acd 80; bm Kb4; ce 32702; dm 33; pm Kb4; 
k7/P3p3/1Pp1P3/1pP3pp/2p3p1/K1Pp4/3P1P1P/8 w - - acd 67; bm Kb4; ce 32702; dm 33; pm Kb4; 
8/Pk2p1p1/1Pp1P3/1pP3pp/2p5/K1Pp1P2/3P3P/8 w - - acd 80; bm h3; ce 32700; dm 34; pm h3; 
8/Pk2p3/1Pp1P3/1pP3pp/2p3p1/2Pp4/1K1P1P1P/8 w - - acd 69; bm Ka3; ce 32700; dm 34; pm Ka3; 
k7/P3p1p1/1Pp1P2p/1pP3p1/2p5/K1Pp1P2/3P3P/8 w - - acd 80; bm Kb4; ce 32700; dm 34; pm Kb4; 
8/Pk2p1p1/1Pp1P2p/1pP3p1/2p5/2Pp1P2/1K1P3P/8 w - - acd 80; bm Ka3; ce 32698; dm 35; pm Ka3; 
k7/P3p1p1/1Pp1P2p/1pP3p1/2p5/2Pp1P2/3P3P/1K6 w - - acd 80; bm Kb2; ce 32696; dm 36; pm Kb2; 
k7/P3p1p1/1Pp1P2p/1pP3p1/2p5/2Pp1P2/K2P3P/8 w - - acd 80; bm Kb2; ce 32696; dm 36; pm Kb2; 
k7/P3p3/1Pp1P3/1pP3pp/2p3p1/2Pp4/K2P1P1P/8 w - - acd 73; bm Kb2; ce 32696; dm 36; pm Kb2; 
8/Pk2p1p1/1Pp1P2p/1pP3p1/2p5/2Pp1P2/3P3P/2K5 w - - acd 75; bm Kb1; ce 32694; dm 37; pm Kb1; 
8/Pk2p1p1/1Pp1P2p/1pP3p1/2p5/K1Pp1P2/3P3P/8 w - - acd 80; bm Ka2; ce 32694; dm 37; pm Ka2; 
8/Pk2p3/1Pp1P3/1pP3pp/2p3p1/K1Pp4/3P1P1P/8 w - - acd 75; bm Ka2; ce 32694; dm 37; pm Ka2; 
8/Pk2p3/1Pp1P3/KpP3pp/2p3p1/2Pp4/3P1P1P/8 w - - acd 77; bm Kb4; ce 32692; dm 38; pm Kb4; 
k7/P3p1p1/1Pp1P2p/1pP3p1/1Kp5/2Pp1P2/3P3P/8 w - - acd 80; bm Ka3; ce 32692; dm 38; pm Ka3; 
k7/P3p1p1/1Pp1P2p/1pP3p1/2p5/2Pp1P2/1K1P3P/8 w - - acd 77; bm Kc1; ce 32692; dm 38; pm Kc1; 
8/Pk2p1p1/1Pp1P2p/KpP3p1/2p5/2Pp1P2/3P3P/8 w - - acd 80; bm Kb4; ce 32690; dm 39; pm Kb4; 
8/Pk2p3/1Pp1P2p/1pP3p1/1Kp3p1/2Pp4/3P1P1P/8 w - - acd 79; bm Ka5; ce 32690; dm 39; pm Ka5; 
k7/P3p3/1Pp1P3/1pP3pp/1Kp3p1/2Pp4/3P1P1P/8 w - - acd 79; bm Ka3; ce 32690; dm 39; pm Ka3; 
8/Pk2p1pp/1Pp1P3/1pP3p1/1Kp5/2Pp1P2/3P3P/8 w - - acd 81; bm Ka5; ce 32688; dm 40; pm Ka5; 
k7/P3p3/1Pp1P2p/1pP3p1/2p3p1/K1Pp4/3P1P1P/8 w - - acd 81; bm Kb4; ce 32688; dm 40; pm Kb4; 
8/Pk2p3/1Pp1P2p/1pP3p1/2p3p1/2Pp4/1K1P1P1P/8 w - - acd 83; bm Ka3; ce 32686; dm 41; pm Ka3; 
k7/P3p1pp/1Pp1P3/1pP3p1/2p5/K1Pp1P2/3P3P/8 w - - acd 83; bm Kb4; ce 32686; dm 41; pm Kb4; 
8/Pk2p1pp/1Pp1P3/1pP3p1/2p5/2Pp1P2/1K1P3P/8 w - - acd 85; bm Ka3; ce 32684; dm 42; pm Ka3; 
k7/P3p1pp/1Pp1P3/1pP3p1/2p5/2Pp1P2/3P3P/2K5 w - - acd 87; bm Kb2; ce 32682; dm 43; pm Kb2; 
k7/P3p3/1Pp1P2p/1pP3p1/2p3p1/2Pp4/K2P1P1P/8 w - - acd 87; bm Kb2; ce 32682; dm 43; pm Kb2; 
8/Pk2p1pp/1Pp1P3/1pP3p1/2p5/2Pp1P2/3P3P/3K4 w - - acd 89; bm Kc1; ce 32680; dm 44; pm Kc1; 
8/Pk2p3/1Pp1P2p/1pP3p1/2p3p1/K1Pp4/3P1P1P/8 w - - acd 91; bm Ka2; ce 32678; dm 45; pm Ka2; 
k7/P3p1pp/1Pp1P3/1pP3p1/2p5/2Pp1P2/3P3P/4K3 w - - acd 91; bm Kd1; ce 32678; dm 45; pm Kd1; 
k7/P3p3/1Pp1P2p/1pP3p1/1Kp3p1/2Pp4/3P1P1P/8 w - - acd 91; bm Ka3; ce 32678; dm 45; pm Ka3; 
8/Pk2p1pp/1Pp1P3/1pP3p1/2p5/2Pp1P2/3P1K1P/8 w - - acd 93; bm Ke1; ce 32676; dm 46; pm Ke1; 
8/Pk2p3/1Pp1P2p/KpP3p1/2p3p1/2Pp4/3P1P1P/8 w - - acd 95; bm Kb4; ce 32674; dm 47; pm Kb4; 
k7/P3p1pp/1Pp1P3/1pP3p1/2p5/2Pp1P2/3P3P/5K2 w - - acd 95; bm Ke1; ce 32674; dm 47; pm Ke1; 
8/Pk2p1pp/1Pp1P3/1pP3p1/2p5/2Pp4/3P1P1P/5K2 w - - acd 97; bm f3; ce 32672; dm 48; pm f3; 
8/Pk2p3/1Pp1P1pp/1pP5/1Kp3p1/2Pp4/3P1P1P/8 w - - acd 99; bm Ka5; ce 32670; dm 49; pm Ka5; 
k7/P3p3/1Pp1P1pp/1pP5/2p3p1/K1Pp4/3P1P1P/8 w - - acd 101; bm Kb4; ce 32668; dm 50; pm Kb4; 
8/Pk2p3/1Pp1P1pp/1pP5/2p3p1/2Pp4/1K1P1P1P/8 w - - acd 103; bm Ka3; ce 32666; dm 51; pm Ka3; 
8/Pk2p3/1Pp1P1pp/1pP5/2p3p1/K1Pp4/3P1P1P/8 w - - acd 105; bm Ka2; ce 32664; dm 52; pm Ka2; 
k7/P3p3/1Pp1P1pp/1pP5/2p3p1/2Pp4/K2P1P1P/8 w - - acd 105; bm Kb2; ce 32664; dm 52; pm Kb2; 
k7/P3p3/1Pp1P1pp/1pP5/1Kp3p1/2Pp4/3P1P1P/8 w - - acd 107; bm Ka3; ce 32662; dm 53; pm Ka3; 
8/Pk2p3/1Pp1P1pp/KpP5/2p3p1/2Pp4/3P1P1P/8 w - - acd 109; bm Kb4; ce 32660; dm 54; pm Kb4; 
k7/P3p1p1/1Pp1P2p/1pP5/2p3p1/K1Pp4/3P1P1P/8 w - - acd 117; bm Kb4; ce 32652; dm 58; pm Kb4; c9 "HHdbVI.1156870.013a.57979"; 
8/Pk2p1p1/1Pp1P2p/1pP5/1Kp3p1/2Pp4/3P1P1P/8 w - - acd 119; bm Ka5; ce 32650; dm 59; pm Ka5; c9 "HHdbVI.1156872.014a.57979"; 
8/Pk2p1p1/1Pp1P2p/1pP5/2p3p1/2Pp4/1K1P1P1P/8 w - - acd 119; bm Ka3; ce 32650; dm 59; pm Ka3; c9 "HHdbVI.1156868.012a.57979"; 
8/Pk2p1p1/1Pp1P2p/1pP5/2p3p1/K1Pp4/3P1P1P/8 w - - acd 133; bm Ka2; ce 32636; dm 66; pm Ka2; c9 "HHdbVI.1156864.010a.57979"; 
k7/P3p1p1/1Pp1P2p/1pP5/2p3p1/2Pp4/K2P1P1P/8 w - - acd 133; bm Kb2; ce 32636; dm 66; pm Kb2; c9 "HHdbVI.1156866.011a.57979"; 
k7/P3p1p1/1Pp1P2p/1pP5/1Kp3p1/2Pp4/3P1P1P/8 w - - acd 135; bm Ka3; ce 32634; dm 67; pm Ka3; c9 "HHdbVI.1156862.009a.57979"; 
8/Pk2p1p1/1Pp1P2p/KpP5/2p3p1/2Pp4/3P1P1P/8 w - - acd 137; bm Kb4; ce 32632; dm 68; pm Kb4; c9 "HHdbVI.1156860.008a.57979"; 
8/Pk2p1pp/1Pp1P3/1pP5/1Kp3p1/2Pp4/3P1P1P/8 w - - acd 139; bm Ka5; ce 32630; dm 69; pm Ka5; c9 "HHdbVI.1156858.007a.57979"; 
k7/P3p1pp/1Pp1P3/1pP5/2p3p1/K1Pp4/3P1P1P/8 w - - acd 141; bm Kb4; ce 32628; dm 70; pm Kb4; c9 "HHdbVI.1156856.006a.57979"; 
8/Pk2p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/1K1P1P1P/8 w - - acd 143; bm Ka3; ce 32626; dm 71; pm Ka3; c9 "HHdbVI.1156854.005a.57979"; 
8/Pk2p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/3P1P1P/2K5 w - - acd 149; bm Kb1; ce 32620; dm 74; pm Kb1; 
8/Pk2p1pp/1Pp1P3/1pP5/2p3p1/K1Pp4/3P1P1P/8 w - - acd 149; bm Ka2; ce 32620; dm 74; pm Ka2; c9 "HHdbVI.1156850.003a.57979"; 
k7/P3p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/1K1P1P1P/8 w - - acd 151; bm Ka3; ce 32618; dm 75; pm Ka3; 
8/Pk2p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/3P1P1P/4K3 w - - acd 155; bm Kd1; ce 32614; dm 77; pm Kd1; 
k7/P3p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/K2P1P1P/8 w - - acd 155; bm Kb1; ce 32614; dm 77; pm Kb1; c9 "HHdbVI.1156852.004a.57979"; 
8/Pk2p1pp/1Pp1P3/1pP3p1/2p5/2Pp4/3P1P1P/7K w - - acd 70; bm Kg2; ce 9615; pm Kg2; id "ChestDB.06542"; 
8/Pk2p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/3P1PKP/8 w - - acd 70; bm Kf1; ce 9615; pm Kf1; 
k7/P3p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/3P1P1P/3K4 w - - acd 70; bm Kc1; ce 9615; pm Kc1; 
k7/P3p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/3P1P1P/5K2 w - - acd 70; bm Ke1; ce 9615; pm Ke1; 
k7/P3p1pp/1Pp1P3/1pP3p1/2p5/2Pp4/3P1PKP/8 w - - acd 70; bm Kf1; ce 1384; pm Kf1; 
8/Pk2p1p1/1Pp1P2p/1pP5/1Kp3p1/2Pp4/3P1P1P/8 b - - acd 70; bm Ka8; ce 0; pm Ka8; c9 "HHdbVI.1156861.008b.57979"; 
k7/P3p1pp/1Pp1P3/1pP3p1/2p5/2Pp4/3P1P1P/5K2 b - - acd 73; bm g4; ce -500; pm g4; 
8/Pk2p1pp/1Pp1P3/1pP3p1/2p5/2Pp4/3P1PKP/8 b - - acd 70; bm g4; ce -1161; pm g4; 
8/Pk2p1p1/1Pp1P2p/1pP5/2p3p1/2Pp4/K2P1P1P/8 b - - acd 70; bm Ka8; ce -9615; pm Ka8; c9 "HHdbVI.1156865.010b.57979"; 
8/Pk2p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/1K1P1P1P/8 b - - acd 70; bm Ka8; ce -9615; pm Ka8; 
8/Pk2p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/3P1P1P/3K4 b - - acd 70; bm g6; ce -9615; pm g6; 
8/Pk2p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/3P1P1P/5K2 b - - acd 70; bm h6; ce -9615; pm h6; 
8/Pk2p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/K2P1P1P/8 b - - acd 70; bm Ka8; ce -9615; pm Ka8; c9 "HHdbVI.1156851.003b.57979"; 
8/Pk2p1pp/1Pp1P3/1pP5/2p3p1/K1Pp4/3P1P1P/8 b - - acd 70; bm Ka8; ce -9615; pm Ka8; c9 "HHdbVI.1156855.005b.57979"; 
8/Pk2p1pp/1Pp1P3/KpP5/2p3p1/2Pp4/3P1P1P/8 b - - acd 70; bm h6; ce -9615; c7 "No. 295654 (id: P1299269) Kn oppel, Jan Heribert source 1: S oslanger, No. 4, 1969 source 2: Springaren, 1962 stipulation: #66 solution: 1.Kb4 Ka8 2.Ka3 Kb7 3.Ka2 Ka8 4.Kb2 Kb7 5.Ka3 Ka8 6.Kb4 Kb7 7.Ka5 g6 8.Kb4 Ka8 9.Ka3 Kb7 10.Ka2 Ka8 11.Kb2 Kb7 12.Ka3 Ka8 13.Kb4 Kb7 14.Ka5 g5 15.Kb4 Ka8 16.Ka3 Kb7 17.Ka2 Ka8 18.Kb2 Kb7 19.Ka3 Ka8 20.Kb4 Kb7 21.Ka5 h6 22.Kb4 Ka8 23.Ka3 Kb7 24.Ka2 Ka8 25.Kb2 Kb7 26.Ka3 Ka8 27.Kb4 Kb7 28.Ka5 h5 29.Kb4 Ka8 30.Ka3 Kb7 31.Ka2 Ka8 32.Kb2 Kb7 33.Ka3 Ka8 34.Kb4 Kb7 35.Ka5 h4 36.Kb4 Ka8 37.Ka3 Kb7 38.Ka2 Ka8 39.Kb2 Kb7 40.Ka3 Ka8 41.Kb4 Kb7 42.Ka5 h3 43.Kb4 Ka8 44.Ka3 Kb7 45.Ka2 Ka8 46.Kb2 Kb7 47.Ka3 Ka8 48.Kb4 Kb7 49.Ka5 g3 50.fxg3 g4 51.Kb4 Ka8 52.Ka3 Kb7 53.Kb2 Ka8 54.Kb1 b4 55.cxb4 c3 56.Kc1 cxd2+ 57.Kxd2 Kb7 58.Kxd3 Ka8 59.b5 Kb7 60.bxc6+ Kxc6 61.a8=D+ Kxc5 62.b7 Kd5 63.b8=D+ Kxe6 64.Ke4 Kf6 65.Dh8+ Kg6 66.Dag8#"; pm h6; c9 "HHdbVI.1156859.007b.57979"; 
k7/P3p1p1/1Pp1P2p/1pP5/2p3p1/K1Pp4/3P1P1P/8 b - - acd 70; bm Kb7; ce -9615; pm Kb7; c9 "HHdbVI.1156863.009b.57979"; 
k7/P3p1pp/1Pp1P3/1pP5/1Kp3p1/2Pp4/3P1P1P/8 b - - acd 70; bm Kb7; ce -9615; pm Kb7; c9 "HHdbVI.1156857.006b.57979"; 
k7/P3p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/1K1P1P1P/8 b - - acd 70; bm Kb7; ce -9615; pm Kb7; c9 "HHdbVI.1156853.004b.57979"; 
k7/P3p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/3P1P1P/2K5 b - - acd 70; bm Kb7; ce -9615; pm Kb7; 
k7/P3p1pp/1Pp1P3/1pP5/2p3p1/2Pp4/3P1P1P/4K3 b - - acd 70; bm g6; ce -9615; pm g6; 
k7/P3p1pp/1Pp1P3/1pP5/2p3p1/K1Pp4/3P1P1P/8 b - - acd 70; bm Kb7; ce -9615; pm Kb7; c9 "HHdbVI.1156849.002b.57979"; 
k7/P3p1p1/1Pp1P2p/1pP5/2p3p1/2Pp4/1K1P1P1P/8 b - - acd 143; bm Kb7; ce -32625; dm -71; pm Kb7; c9 "HHdbVI.1156867.011b.57979"; 
k7/P3p1p1/1Pp1P2p/1pP5/1Kp3p1/2Pp4/3P1P1P/8 b - - acd 119; bm Kb7; ce -32649; dm -59; pm Kb7; c9 "HHdbVI.1156871.013b.57979"; 
8/Pk2p1p1/1Pp1P2p/1pP5/2p3p1/K1Pp4/3P1P1P/8 b - - acd 117; bm Ka8; ce -32651; dm -58; pm Ka8; c9 "HHdbVI.1156869.012b.57979"; 
8/Pk2p1p1/1Pp1P2p/KpP5/2p3p1/2Pp4/3P1P1P/8 b - - acd 113; bm g6; ce -32655; dm -56; pm g6; c9 "HHdbVI.1156873.014b.57979"; 
8/Pk2p3/1Pp1P1pp/1pP5/1Kp3p1/2Pp4/3P1P1P/8 b - - acd 107; bm Ka8; ce -32661; dm -53; pm Ka8; 
8/Pk2p3/1Pp1P1pp/1pP5/2p3p1/2Pp4/K2P1P1P/8 b - - acd 105; bm Ka8; ce -32663; dm -52; pm Ka8; 
k7/P3p3/1Pp1P1pp/1pP5/2p3p1/K1Pp4/3P1P1P/8 b - - acd 105; bm Kb7; ce -32663; dm -52; pm Kb7; 
k7/P3p3/1Pp1P1pp/1pP5/2p3p1/2Pp4/1K1P1P1P/8 b - - acd 103; bm Kb7; ce -32665; dm -51; pm Kb7; 
8/Pk2p3/1Pp1P1pp/1pP5/2p3p1/K1Pp4/3P1P1P/8 b - - acd 101; bm Ka8; ce -32667; dm -50; pm Ka8; 
8/Pk2p1pp/1Pp1P3/1pP3p1/2p5/2Pp1P2/3P3P/5K2 b - - acd 99; bm Ka8; ce -32669; dm -49; pm Ka8; 
k7/P3p3/1Pp1P1pp/1pP5/1Kp3p1/2Pp4/3P1P1P/8 b - - acd 99; bm Kb7; ce -32669; dm -49; pm Kb7; 
8/Pk2p3/1Pp1P1pp/KpP5/2p3p1/2Pp4/3P1P1P/8 b - - acd 97; bm h5; ce -32671; dm -48; pm h5; 
k7/P3p1pp/1Pp1P3/1pP3p1/2p5/2Pp1P2/3P1K1P/8 b - - acd 97; bm Kb7; ce -32671; dm -48; pm Kb7; 
8/Pk2p1pp/1Pp1P3/1pP3p1/2p5/2Pp1P2/3P3P/4K3 b - - acd 95; bm Ka8; ce -32673; dm -47; pm Ka8; 
8/Pk2p3/1Pp1P2p/1pP3p1/1Kp3p1/2Pp4/3P1P1P/8 b - - acd 95; bm Ka8; ce -32673; dm -47; pm Ka8; 
k7/P3p1pp/1Pp1P3/1pP3p1/2p5/2Pp1P2/1K1P3P/8 b - - acd 93; bm Kb7; ce -32675; dm -46; pm Kb7; 
k7/P3p1pp/1Pp1P3/1pP3p1/2p5/2Pp1P2/3P3P/3K4 b - - acd 93; bm Kb7; ce -32675; dm -46; pm Kb7; 
k7/P3p3/1Pp1P2p/1pP3p1/2p3p1/K1Pp4/3P1P1P/8 b - - acd 93; bm Kb7; ce -32675; dm -46; pm Kb7; 
8/Pk2p1pp/1Pp1P3/1pP3p1/2p5/2Pp1P2/3P3P/2K5 b - - acd 91; bm Ka8; ce -32677; dm -45; pm Ka8; 
8/Pk2p1pp/1Pp1P3/1pP3p1/2p5/K1Pp1P2/3P3P/8 b - - acd 91; bm Ka8; ce -32677; dm -45; pm Ka8; 
8/Pk2p3/1Pp1P2p/1pP3p1/2p3p1/2Pp4/K2P1P1P/8 b - - acd 91; bm Ka8; ce -32677; dm -45; pm Ka8; 
k7/P3p1pp/1Pp1P3/1pP3p1/1Kp5/2Pp1P2/3P3P/8 b - - acd 89; bm Kb7; ce -32679; dm -44; pm Kb7; 
k7/P3p3/1Pp1P2p/1pP3p1/2p3p1/2Pp4/1K1P1P1P/8 b - - acd 89; bm Kb7; ce -32679; dm -44; pm Kb7; 
8/Pk2p3/1Pp1P2p/1pP3p1/2p3p1/K1Pp4/3P1P1P/8 b - - acd 87; bm Ka8; ce -32681; dm -43; pm Ka8; 
8/Pk2p1p1/1Pp1P2p/1pP3p1/1Kp5/2Pp1P2/3P3P/8 b - - acd 81; bm h5; ce -32687; dm -40; pm h5; 
8/Pk2p1pp/1Pp1P3/KpP3p1/2p5/2Pp1P2/3P3P/8 b - - acd 81; bm g6; ce -32687; dm -40; pm g6; 
k7/P3p1p1/1Pp1P2p/1pP3p1/2p5/K1Pp1P2/3P3P/8 b - - acd 80; bm h5; ce -32687; dm -37; pm h5; 
k7/P3p3/1Pp1P2p/1pP3p1/1Kp3p1/2Pp4/3P1P1P/8 b - - acd 81; bm Kb7; ce -32687; dm -40; pm Kb7; 
8/Pk2p1p1/1Pp1P2p/1pP3p1/2p5/2Pp1P2/1K1P3P/8 b - - acd 80; bm Ka8; ce -32689; dm -39; pm Ka8; 
8/Pk2p3/1Pp1P2p/KpP3p1/2p3p1/2Pp4/3P1P1P/8 b - - acd 79; bm h5; ce -32689; dm -39; pm h5; 
8/Pk2p3/1Pp1P3/1pP3pp/1Kp3p1/2Pp4/3P1P1P/8 b - - acd 77; bm Ka8; ce -32691; dm -38; pm Ka8; 
k7/P3p1p1/1Pp1P2p/1pP3p1/2p5/2Pp1P2/3P3P/2K5 b - - acd 80; bm h5; ce -32691; dm -38; pm h5; 
k7/P3p3/1Pp1P3/1pP3pp/2p3p1/K1Pp4/3P1P1P/8 b - - acd 75; bm Kb7; ce -32693; dm -37; pm Kb7; 
8/Pk2p1p1/1Pp1P2p/1pP3p1/2p5/2Pp1P2/3P3P/1K6 b - - acd 80; bm h5; ce -32695; dm -36; pm h5; 
8/Pk2p1p1/1Pp1P2p/1pP3p1/2p5/2Pp1P2/K2P3P/8 b - - acd 80; bm Ka8; ce -32695; dm -36; pm Ka8; 
8/Pk2p3/1Pp1P3/1pP3pp/2p3p1/2Pp4/K2P1P1P/8 b - - acd 73; bm Ka8; ce -32695; dm -36; pm Ka8; 
k7/P3p1p1/1Pp1P2p/1pP3p1/2p5/2Pp1P2/1K1P3P/8 b - - acd 80; bm Kb7; ce -32697; dm -35; pm Kb7; 
k7/P3p3/1Pp1P3/1pP3pp/2p3p1/2Pp4/1K1P1P1P/8 b - - acd 71; bm Kb7; ce -32697; dm -35; pm Kb7; 
8/Pk2p1p1/1Pp1P2p/1pP3p1/2p5/K1Pp1P2/3P3P/8 b - - acd 80; bm h5; ce -32699; dm -34; pm h5; 
8/Pk2p3/1Pp1P3/1pP3pp/2p3p1/K1Pp4/3P1P1P/8 b - - acd 70; bm Ka8; ce -32699; dm -34; pm Ka8; 
8/Pk2p1p1/1Pp1P3/1pP3pp/2p5/K1Pp1P1P/3P4/8 b - - acd 80; bm Ka8; ce -32701; dm -33; pm Ka8; 
k7/P3p1p1/1Pp1P2p/1pP3p1/1Kp5/2Pp1P2/3P3P/8 b - - acd 80; bm Kb7; ce -32701; dm -33; pm Kb7; 
k7/P3p3/1Pp1P3/1pP3pp/1Kp3p1/2Pp4/3P1P1P/8 b - - acd 70; bm Kb7; ce -32701; dm -33; pm Kb7; 
8/Pk2p1p1/1Pp1P2p/KpP3p1/2p5/2Pp1P2/3P3P/8 b - - acd 80; bm g6; ce -32703; dm -32; pm g6; 
8/Pk2p3/1Pp1P3/KpP3pp/2p3p1/2Pp4/3P1P1P/8 b - - acd 70; bm h4; ce -32703; dm -32; pm h4; 
k7/P3p1p1/1Pp1P3/1pP3pp/1Kp5/2Pp1P1P/3P4/8 b - - acd 80; bm Kb7; ce -32703; dm -32; pm Kb7; 
8/Pk2p1p1/1Pp1P3/KpP3pp/2p5/2Pp1P1P/3P4/8 b - - acd 80; bm g6; ce -32705; dm -31; pm g6; 
8/Pk2p3/1Pp1P3/1pP3p1/1Kp3pp/2Pp4/3P1P1P/8 b - - acd 70; bm Ka8; ce -32705; dm -31; pm Ka8; c9 "HHdbVI.1156917.036b.57979"; 
8/Pk2p1p1/1Pp1P3/1pP3p1/1Kp4p/2Pp1P1P/3P4/8 b - - acd 80; bm Ka8; ce -32707; dm -30; pm Ka8; 
8/Pk2p1p1/1Pp1P3/1pP3p1/2p4p/2Pp1P1P/1K1P4/8 b - - acd 80; bm Ka8; ce -32707; dm -30; pm Ka8; 
8/Pk2p3/1Pp1P1p1/1pP3pp/1Kp5/2Pp1P1P/3P4/8 b - - acd 80; bm Ka8; ce -32707; dm -30; pm Ka8; 
k7/P3p3/1Pp1P3/1pP3p1/2p3pp/K1Pp4/3P1P1P/8 b - - acd 70; bm Kb7; ce -32707; dm -30; pm Kb7; c9 "HHdbVI.1156919.037b.57979"; 
8/Pk2p3/1Pp1P3/1pP3p1/2p3pp/2Pp4/K2P1P1P/8 b - - acd 70; bm Ka8; ce -32709; dm -29; pm Ka8; c9 "HHdbVI.1156921.038b.57979"; 
k7/P3p1p1/1Pp1P3/1pP3p1/2p4p/2Pp1P1P/3P4/2K5 b - - acd 80; bm Kb7; ce -32709; dm -29; pm Kb7; 
k7/P3p1p1/1Pp1P3/1pP3p1/2p4p/K1Pp1P1P/3P4/8 b - - acd 80; bm Kb7; ce -32709; dm -29; pm Kb7; 
k7/P3p3/1Pp1P1p1/1pP3pp/2p5/K1Pp1P1P/3P4/8 b - - acd 80; bm Kb7; ce -32709; dm -29; pm Kb7; 
8/Pk2p1p1/1Pp1P3/1pP3p1/2p4p/2Pp1P1P/3P4/1K6 b - - acd 80; bm Ka8; ce -32711; dm -28; pm Ka8; 
8/Pk2p3/1Pp1P1p1/1pP3pp/2p5/2Pp1P1P/K2P4/8 b - - acd 80; bm Ka8; ce -32711; dm -28; pm Ka8; 
1Rn4k/n1p5/pb1p1N1P/3P3p/7p/p1p1P3/P1P1PP1P/7K b - - acd 70; bm h3; ce -32713; dm -27; pm h3; 
k7/P3p1p1/1Pp1P3/1pP3p1/2p4p/2Pp1P1P/1K1P4/8 b - - acd 80; bm Kb7; ce -32713; dm -27; pm Kb7; 
k7/P3p3/1Pp1P1p1/1pP3pp/2p5/2Pp1P1P/1K1P4/8 b - - acd 80; bm Kb7; ce -32713; dm -27; pm Kb7; 
k7/P3p3/1Pp1P3/1pP3p1/2p3pp/2Pp4/1K1P1P1P/8 b - - acd 70; bm Kb7; ce -32713; dm -27; pm Kb7; c9 "HHdbVI.1156923.039b.57979"; 
1Rn4k/n1p5/pb1p1N1P/3P3p/8/p1p1P2p/P1P1PP1P/6K1 b - - acd 70; bm Bc5; ce -32715; dm -26; pm Bc5; 
8/Pk2p1p1/1Pp1P3/1pP3p1/2p4p/K1Pp1P1P/3P4/8 b - - acd 80; bm Ka8; ce -32715; dm -26; pm Ka8; 
8/Pk2p3/1Pp1P1p1/1pP3pp/2p5/K1Pp1P1P/3P4/8 b - - acd 80; bm Ka8; ce -32715; dm -26; pm Ka8; 
8/Pk2p3/1Pp1P3/1pP3p1/2p3pp/K1Pp4/3P1P1P/8 b - - acd 70; bm Ka8; ce -32715; dm -26; pm Ka8; c9 "HHdbVI.1156925.040b.57979"; 
k7/P3p1p1/1Pp1P3/1pP3p1/1Kp4p/2Pp1P1P/3P4/8 b - - acd 80; bm Kb7; ce -32717; dm -25; pm Kb7; 
k7/P3p3/1Pp1P1p1/1pP3pp/1Kp5/2Pp1P1P/3P4/8 b - - acd 80; bm Kb7; ce -32717; dm -25; pm Kb7; 
k7/P3p3/1Pp1P3/1pP3p1/1Kp3pp/2Pp4/3P1P1P/8 b - - acd 70; bm Kb7; ce -32717; dm -25; pm Kb7; c9 "HHdbVI.1156927.041b.57979"; 
8/Pk2p1p1/1Pp1P3/KpP3p1/2p4p/2Pp1P1P/3P4/8 b - - acd 80; bm g6; ce -32719; dm -24; pm g6; 
8/Pk2p3/1Pp1P1p1/KpP3pp/2p5/2Pp1P1P/3P4/8 b - - acd 80; bm h4; ce -32719; dm -24; pm h4; 
8/Pk2p3/1Pp1P3/KpP3p1/2p3pp/2Pp4/3P1P1P/8 b - - acd 70; bm h3; ce -32719; dm -24; pm h3; c9 "HHdbVI.1156929.042b.57979"; 
8/Pk2p3/1Pp1P1p1/1pP3p1/1Kp4p/2Pp1P1P/3P4/8 b - - acd 80; bm Ka8; ce -32721; dm -23; pm Ka8; 
8/Pk2p3/1Pp1P1p1/1pP3p1/2p4p/2Pp1P1P/1K1P4/8 b - - acd 80; bm Ka8; ce -32721; dm -23; pm Ka8; 
8/Pk2p3/1Pp1P3/1pP3p1/1Kp3p1/2Pp3p/3P1P1P/8 b - - acd 70; bm Ka8; ce -32721; dm -23; pm Ka8; c9 "HHdbVI.1156931.043b.57979"; 
k7/P3p3/1Pp1P1p1/1pP3p1/2p4p/2Pp1P1P/3P4/1K6 b - - acd 80; bm Kb7; ce -32723; dm -22; pm Kb7; 
k7/P3p3/1Pp1P1p1/1pP3p1/2p4p/K1Pp1P1P/3P4/8 b - - acd 80; bm Kb7; ce -32723; dm -22; pm Kb7; 
k7/P3p3/1Pp1P3/1pP3p1/2p3p1/K1Pp3p/3P1P1P/8 b - - acd 70; bm Kb7; ce -32723; dm -22; pm Kb7; c9 "HHdbVI.1156933.044b.57979"; 
8/Pk2p3/1Pp1P1p1/1pP3p1/2p4p/2Pp1P1P/K2P4/8 b - - acd 80; bm Ka8; ce -32725; dm -21; pm Ka8; 
8/Pk2p3/1Pp1P3/1pP3p1/2p3p1/2Pp3p/K2P1P1P/8 b - - acd 70; bm Ka8; ce -32725; dm -21; pm Ka8; c9 "HHdbVI.1156935.045b.57979"; 
k7/P3p3/1Pp1P1p1/1pP3p1/2p4p/2Pp1P1P/1K1P4/8 b - - acd 80; bm Kb7; ce -32727; dm -20; pm Kb7; 
k7/P3p3/1Pp1P3/1pP3p1/2p3p1/2Pp3p/1K1P1P1P/8 b - - acd 70; bm Kb7; ce -32727; dm -20; pm Kb7; c9 "HHdbVI.1156937.046b.57979"; 
8/Pk2p3/1Pp1P1p1/1pP3p1/2p4p/K1Pp1P1P/3P4/8 b - - acd 80; bm Ka8; ce -32729; dm -19; pm Ka8; 
8/Pk2p3/1Pp1P3/1pP3p1/2p3p1/K1Pp3p/3P1P1P/8 b - - acd 70; bm Ka8; ce -32729; dm -19; pm Ka8; c9 "HHdbVI.1156939.047b.57979"; 
k7/P3p3/1Pp1P1p1/1pP3p1/1Kp4p/2Pp1P1P/3P4/8 b - - acd 80; bm Kb7; ce -32731; dm -18; pm Kb7; 
k7/P3p3/1Pp1P3/1pP3p1/1Kp3p1/2Pp3p/3P1P1P/8 b - - acd 70; bm Kb7; ce -32731; dm -18; pm Kb7; c9 "HHdbVI.1156941.048b.57979"; 
8/Pk2p3/1Pp1P1p1/KpP3p1/2p4p/2Pp1P1P/3P4/8 b - - acd 80; bm g4; ce -32733; dm -17; pm g4; 
8/Pk2p3/1Pp1P3/KpP3p1/2p3p1/2Pp3p/3P1P1P/8 b - - acd 84; bm g3; ce -32733; dm -17; pm g3; c9 "HHdbVI.1156943.049b.57979"; 
8/Pk2p3/1Pp1P1p1/KpP5/2p3Pp/2Pp3P/3P4/8 b - - acd 80; bm g5; ce -32735; dm -16; pm g5; 
8/Pk2p3/1Pp1P3/KpP3p1/2p5/2Pp2Pp/3P3P/8 b - - acd 73; bm g4; ce -32735; dm -16; pm g4; c9 "HHdbVI.1156945.050b.57979"; 
8/Pk2p3/1Pp1P3/1pP3p1/1Kp3Pp/2Pp3P/3P4/8 b - - acd 80; bm Ka8; ce -32737; dm -15; pm Ka8; 
8/Pk2p3/1Pp1P3/1pP5/1Kp3p1/2Pp2Pp/3P3P/8 b - - acd 70; bm Ka8; ce -32737; dm -15; pm Ka8; c9 "HHdbVI.1156947.051b.57979"; 
k7/P3p3/1Pp1P3/1pP3p1/2p3Pp/K1Pp3P/3P4/8 b - - acd 80; bm Kb7; ce -32739; dm -14; pm Kb7; 
k7/P3p3/1Pp1P3/1pP5/2p3p1/K1Pp2Pp/3P3P/8 b - - acd 70; bm Kb7; ce -32739; dm -14; pm Kb7; c9 "HHdbVI.1156949.052b.57979"; 
8/Pk2p3/1Pp1P3/1pP3p1/2p3Pp/2Pp3P/1K1P4/8 b - - acd 80; bm Ka8; ce -32741; dm -13; pm Ka8; 
8/Pk2p3/1Pp1P3/1pP5/2p3p1/2Pp2Pp/K2P3P/8 b - - acd 70; bm b4; ce -32741; dm -13; pm b4; c9 "HHdbVI.1156951.053b.57979"; 
k7/P3p3/1Pp1P1p1/2P3p1/1Pp4p/3p1P1P/3P4/1K6 b - - acd 80; bm g4; ce -32743; dm -12; pm g4; 
k7/P3p3/1Pp1P3/1pP3p1/2p3Pp/2Pp3P/3P4/1K6 b - - acd 80; bm Kb7; ce -32743; dm -12; pm Kb7; 
8/Pk2p3/1Pp1P3/1pP3p1/2p3Pp/2Pp3P/3P4/2K5 b - - acd 80; bm Ka8; ce -32745; dm -11; pm Ka8; 
k7/P3p3/1Pp1P3/1pP5/2p3p1/2Pp2Pp/1K1P3P/8 b - - acd 199; bm Kb7; ce -32747; dm -10; pm Kb7; c9 "HHdbVI.1156953.054b.57979"; 
8/Pk2p3/1Pp1P3/1pP5/2p3p1/K1Pp2Pp/3P3P/8 b - - acd 211; bm Ka8; ce -32749; dm -9; pm Ka8; c9 "HHdbVI.1156955.055b.57979"; 
8/Pk2p3/1Pp1P3/2P3p1/1Pp3Pp/3p3P/3P4/2K5 b - - acd 80; bm Ka8; ce -32749; dm -9; pm Ka8; 
8/Pk2p3/1Pp1P3/2P3p1/1P4Pp/2Pp3P/8/2K5 b - - acd 80; bm d2+; ce -32751; dm -8; pm d2+; 
k7/P3p3/1Pp1P3/1pP5/1Kp3p1/2Pp2Pp/3P3P/8 b - - acd 204; bm Kb7; ce -32751; dm -8; pm Kb7; c9 "HHdbVI.1156957.056b.57979"; 
8/Pk2p3/1Pp1P3/KpP5/2p3p1/2Pp2Pp/3P3P/8 b - - acd 70; bm b4; ce -32753; dm -7; pm b4; c9 "HHdbVI.1156959.057b.57979"; 
k7/P3p3/1Pp1P3/1PP3p1/6Pp/2Pp3P/8/2K5 b - - acd 80; bm Kb7; ce -32753; dm -7; pm Kb7; 
8/Pk2p3/1Pp1P3/2P5/1Kp3p1/2Pp2Pp/3P3P/8 b - - acd 245; bm Ka8; ce -32755; dm -6; pm Ka8; c9 "HHdbVI.1156961.058b.57979"; 
k7/P3p3/1Pp1P3/1PP3p1/6Pp/2P4P/3K4/8 b - - acd 80; bm Kb7; ce -32755; dm -6; pm Kb7; 
k7/P3p3/1PP1P3/1p4p1/6Pp/2P4P/3K4/8 b - - acd 80; bm b4; ce -32757; dm -5; pm b4; 
k7/P3p3/1Pp1P3/K1P5/2p3p1/2Pp2Pp/3P3P/8 b - - acd 70; bm Kb7; ce -32757; dm -5; pm Kb7; c9 "HHdbVI.1156963.059b.57979"; 
k7/P3p3/1PP1P3/6p1/1pP3Pp/7P/3K4/8 b - - acd 80; bm b3; ce -32759; dm -4; pm b3; 
Q7/1k2p3/1Pp1P3/K1P5/2p3p1/2Pp2Pp/3P3P/8 b - - acd 999; bm Kxa8; ce -32759; dm -4; pm Kxa8; c9 "HHdbVI.1156965.060b.57979"; 
k7/4p3/KPp1P3/2P5/2p3p1/2Pp2Pp/3P3P/8 b - - acd 999; bm Kb8; ce -32761; dm -3; pm Kb8; c9 "HHdbVI.1156967.061b.57979"; 
k7/P1P1p3/1P2P3/6p1/2P3Pp/1p5P/3K4/8 b - - acd 80; bm Kb7; ce -32761; dm -3; pm Kb7; 
1k6/1P2p3/K1p1P3/2P5/2p3p1/2Pp2Pp/3P3P/8 b - - acd 999; bm Kc7; ce -32763; dm -2; pm Kc7; c9 "HHdbVI.1156969.062b.57979"; 
Q7/1kP1p3/1P2P3/6p1/2P3Pp/1p5P/3K4/8 b - - acd 80; bm Kxb6; ce -32763; dm -2; pm Kxb6; 
8/KPk1p3/2p1P3/2P5/2p3p1/2Pp2Pp/3P3P/8 b - - acd 999; bm Kd8; ce -32765; dm -1; pm Kd8; c9 "HHdbVI.1156971.063b.57979"; 
Q1Q5/4p3/1k2P3/6p1/2P3Pp/1p5P/3K4/8 b - - acd 80; bm b2; ce -32765; dm -1; pm b2;
However, I was only able to find a mate solution for this one:
8 
7 
6 
5 
4 
3 
2 
1 
abcdefgh

R1n4k/n1p5/pb1p1N1P/3P3p/7p/p1p1P3/P1P1PP1P/7K w - - acd 70; bm Rb8; ce 32712; c7 "No. 309494 (id: P1402334) Rotenberg, Jacques; Loustau, Jean-Marc source 1: Phenix, 1993-1994 stipulation: #34 solution: 1.Tb8! h3 2.Kg1 Lc5 3.Kf1 Lb6 4.Ke1 Lc5 5.Kd1 Lb6 6.Kc1 Lc5 7.Kb1 Lb6 8.Ka1 h4 9.Kb1 Lc5 10.Kc1 Lb6 11.Kd1 Lc5 12.Ke1 Lb6 13.Kf1 Lc5 14.Kg1 Lb6 15.Kh1 a5 16.Kg1 Lc5 17.Kf1 Lb6 18.Ke1 Lc5 19.Kd1 Lb6 20.Kc1 Lc5 21.Kb1 Lb6 22.Ka1 a4 23.Kb1 Lc5 24.Kc1 Lb6 25.Kd1 Lc5 26.Ke1 Lb6 27.Kf1 Lc5 28.Kg1 Lb6 29.Kh1 Lc5! 30.Tb1 Ld4 31.exd4 Se7 32.Tg1 Sg6 33.Txg6 ...34.Tg8#"; dm 28; pm Rb8; pv Rb8 h3 Kg1 Bc5 Rb1 Nb6 Kh1 Nd7 Nxd7 Kh7 Nxc5 Nc8 Nxa6 Nb6 Nxc7 Nd7 f3 Ne5 Ne6 Kxh6 Rb3 Kg6 Rxc3 Nd7 Rxa3 Kf6 e4 Nb6 Rb3 Nc4 a4 h4 Rc3 Nd2 a5 Nf1 a6 Ng3+ hxg3 hxg3 a7 Kg6 a8=Q g2+ Kg1 h2+ Kxg2 h1=Q+ Kxh1 Kf7 Qf8+ Kg6 Qg7+ Kh5 Qg5+; id "ChestDB.06430";

Which appears to be a mate in 28 or less (though the key move in the original problem is correct).

For this one, despite all the helpful precursor positions to analyze, I have not yet driven to mate:
8 
7 
6 
5 
4 
3 
2 
1 
abcdefgh

8/Pk2p1pp/1Pp1P3/1pP3p1/2p5/2Pp4/3P1P1P/7K w - - acd 70; bm Kg2; ce 9615; pm Kg2; pv Kg2 Ka8 Kf1 Kb7 f3 Ka8 Kf2 Kb7 Ke1 Ka8 Kd1 Kb7 Kc1 Ka8 Kb2 Kb7 Ka3 Ka8 Kb4 Kb7 Ka5 h6 Kb4 Ka8 Ka3 Kb7 Kb2 Ka8 Kc1 Kb7 Kb1 Ka8 Kb2 Kb7 Ka3 Ka8 Kb4 Kb7 Ka5 h5 h3 h4 Kb4 Ka8 Ka3 Kb7 Kb2 Ka8 Kc1 Kb7 Kb1 Ka8 Kb2 Kb7 Ka3 Ka8 Kb4 Kb7 Ka5 g6 Kb4 Ka8 Ka3 Kb7 Kb2 Ka8 Kb1 b4 cxb4 c3; id "ChestDB.06542";

However, I think in a couple days the solution will fall out. It is currently hung analyzing on ply 72 (two plies from the start of the problem), failing high over and over. It seems that the first two or three moves are by far the most difficult. Analysis powers through all the other child positions very quickly.
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acase
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Joined: Wed Mar 15, 2006 1:14 am
Location: Columbus, Ohio USA
Full name: Andrew R Case

Re: 8 hard positions from the Chest database

Post by acase »

peter wrote: ↑Sat Mar 30, 2024 8:29 pm
peter wrote: ↑Sat Mar 30, 2024 3:08 pm
peter wrote: ↑Sat Mar 30, 2024 12:39 pm
Dann Corbit wrote: ↑Fri Mar 29, 2024 7:39 pm These are the only 8 positions for which I have not found a checkmate solution:
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abcdefgh

2r1b1Q1/6p1/2P5/5P2/1p2K3/pPp5/n2P4/1B2k3 w - - acd 44; bm Kf4; ce 630; c2 "#23;"; pm Kf4; pv Kf4; id "ChestDB.06301";
Maybe not only DTM but bm could be wrong too?
Sting favors 1.Qe6, Huntsman get's this output with some Forward- Backward from and to these first 5 moves

2r1b1Q1/6p1/2P5/5P2/1p2K3/pPp5/n2P4/1B2k3 w - - 0 1
1. Qe6 Bf7 2. Qxc8 cxd2 3. Bc2 Nc3+ 4. Ke3 d1=Q 5. Bxd1 Kxd1

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abcdefgh

2Q5/5bp1/2P5/5P2/1p6/pPn1K3/8/3k4 w - - 0 1

Analysis by The Huntsman 1:

6.c7 Kc2 7.Qb7 a2 8.Qa6 Kb2 9.c8Q a1Q 10.Qxa1+ Kxa1 11.Qf8 Bh5 12.Kd3 Kb2 13.Qxb4 Na2 14.Qb7 Nc1+ 15.Kd2 Nxb3+ 16.Kd3 Be2+ 17.Kxe2 Kc3 18.Qxg7+ Kc4 19.Ke3 Nc5 20.Qd4+ Kb5 21.Qd5 Kb6 22.f6 Na6 23.f7 Nc7 24.Qd6+ Kb5 25.Qxc7 Ka4 26.f8Q Kb3 27.Qfb8+ Ka3 28.Qca7#
Depth: 63/46 00:00:00 13858kN
After 1.Qe6 Bf7:

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abcdefgh

2r5/5bp1/2P1Q3/5P2/1p2K3/pPp5/n2P4/1B2k3 w - - 0 1

Analysis by The Huntsman 1:

2.Qxc8 cxd2 3.Bc2 Nc3+ 4.Ke3 a2 5.Qa6 Be8 6.c7 Bd7 7.Qa8 d1N+ 8.Bxd1 Nxd1+ 9.Kd4 Nc3 10.Kc5 Kd2 11.Kxb4 Bxf5 12.Qg2+ Ne2 13.Qxg7 Bc8 14.Qb2+ Ke3 15.Qxa2 Bg4 16.Qa6 Ng3 17.Kc5 Ne2 18.c8Q Bxc8 19.Qxc8 Kf4 20.Kc4 Kf3 21.Qf5+ Ke3 22.Qg5+ Kf3 23.b4 Ng3 24.b5 Ne4 25.Qd5 Ke3 26.Qd4+ Kf3 27.b6 Ng3 28.Qd3+ Kg4 29.b7 Kh4 30.b8Q Nh5 31.Qe4+ Kh3 32.Qf3+ Kh4 33.Qh2+ Kg5 34.Qhxh5#
Depth: 60/66 00:01:00 2992MN

Output with even shorter DTM I get after 1...Bxc6, 1...Rxc6, 1...Kd1, 1...Bh5 but to keep all these and other alternatives at 1st move of Black's in 32G hash in reasonable hardware- time together with 1st move of White's I gave up trying. One more full move backward to original starting position I'm leaving for good, regards
Excellent analysis as usual Peter, I did a forward-backwards myself with several different engines on this position and came up with something similar to yours:



The thing that makes this one so tough is that there are SEVERAL different moves (duals) that lead to the same outcome, about a mate in 34 for the 1.Qe6 variation, and I'm sure there are several different duals for the 1.Kf4 variation.
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peter
Posts: 3338
Joined: Sat Feb 16, 2008 7:38 am
Full name: Peter Martan

Re: 8 hard positions from the Chest database

Post by peter »

acase wrote: ↑Sat Mar 30, 2024 11:25 pm I did a forward-backwards myself with several different engines on this position and came up with something similar to yours:



The thing that makes this one so tough is that there are SEVERAL different moves (duals) that lead to the same outcome, about a mate in 34 for the 1.Qe6 variation, and I'm sure there are several different duals for the 1.Kf4 variation.
Yet I don't see 1.Kf4 giving nearly as short DTM as 1.Qe6 does, as far as I saw about ten moves more for the originally (in Chest.epd) given solution, anyhow #23 seems unrealistic at all. Would be interesting to know any source, if it was a study (don't think so) author could have a thematic reason to prefer Kf4 without caring for exact DTM and maybe I completely missed such a point and for 20 moves (Kf4) differing tactical hot shots that even Huntsman doesn't get on its own neither, that seems rather unlikely to me.
As long as I don't have any other sources or much shorter variants than ours, I'd say as well best move as DTM in Chest.epd is simply wrong, regards
Peter.
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acase
Posts: 994
Joined: Wed Mar 15, 2006 1:14 am
Location: Columbus, Ohio USA
Full name: Andrew R Case

Re: 8 hard positions from the Chest database

Post by acase »

For the "mate in 125" by Otto Blathy, here is the INTENDED solution for that one courtesy of Jon (Nordlandia):



BUT, This one is COOKED BIG TIME and ends up being a mate in 55-59 as our very good friend Vincent pointed out YEARS ago that at some point White plays Bxf4 or Bxh4 and then more than cuts the mate in half, In my pgn I am showing a mate in 55, but as usual there may be better moves than I am showing, but I firmly believe that this mate CAN be shortened to NO MORE than 59 moves:



As usual if anyone sees any improvements for either side in my pgn than please post them.
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