Mate in ?

[Eelco de Groot]

Hello,

from a thread by Ted Summers a while ago http://www.talkchess.com/forum/viewtopic.php?t=19814

Toga has trouble evaluting correctly the following key position, after

[Event "?"]
[Site "?"]
[Date "2008.03.15"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[SetUp "1"]
[FEN "2r3k1/6pp/3pp1P1/1pP5/1P6/P4R2/5K2/8 w - -"]

1. c6 Rxc6 2. Rf8+ Kxf8 3. gxh7 Rc2+ 4. Kg3 Rc3+ 5. Kg4
Rc4+ 6. Kg5 Rh4 7. Kxh4 g5+ 8. Kxg5 Kg7 9. h8=Q+ Kxh8
10. Kg6 {!} {The only winning move in this position, because after e.g. Kf6 a black pawn can promote on a1 (after a4 bxa4 b5) giving check at the same time and the black king also isn't confined to the back row and therefore not in check after White promotes} *


[d]7k/8/3pp1K1/1p6/1P6/P7/8/8 b - -

Now Toga finds a mate in thirteen after 10. Kg6, diagrammed position which is better than the QSearch explosion I had before but I'm not sure the number of moves to mate is correct.

Chess Tiger 2007.1 Gambit correctly finds 10.Kg6! and gives a mate in 9 at plydepth 26 after 10. Kg6 Kg8, takes long to complete the following plydepth but still a mate in 9. It is possible Chess Tiger uses a different counting and other engines would call it mate in ten, I can't remember exactly but I seem to recall it was something like that. Tiger's three best moves at ply 27 are:

00:25:55.1 Mate in 9 27 1605429060 a4 bxa4 b5 Kf8 b6 Ke7 b7 a3 b8Q a2 Qa7+ Kd8 Kf6 a1Q+ Qxa1 e5 Kf7 Kd7 Qa8 d5 Qxd5+ Kc7
00:25:59.0 -9,33 27 1609251731 Kf6 d5 Ke5 Kg7 Kd4 Kf6 Kd3 e5 Ke3 Kf5 Kd3 e4+ Ke3 d4+ Kxd4 Kf4 Kc3 e3 Kd3 Kf3 Kd4 e2 Kc5 e1Q Kxb5 Qe8+ Kc4 Qe2+ Kc5
00:25:59.8 -9,33 27 1609806277 Kg5 Kf7 Kf4 d5 Ke5 Ke7 Kd4 Kf6 Kd3 e5 Ke3 Kf5 Kd3 e4+ Ke3 d4+ Kxd4 Kf4 Kc3 e3 Kd3 Kf3 Kd4 e2 Kc5 e1Q Kxb5 Qe8+ Kc4 Qe2+ Kc5

Toga Checkov output was now for Build 30, one halfmove earlier after 10. Kg6:


[d]7k/8/3pp1K1/1p6/1P6/P7/8/8 b - -

Engine: Toga 1.5 Checkov_beta1 bb5men (Athlon 2009 MHz, 256 MB, Build 30 14-03-2008 1h 20m, no bitbases access)
by Letouzey, Gaksch, Pudas and de Groot

1/02 0:00 +0.81 10...d5 11.Kg5 (8)

2/04 0:00 +1.12 10...d5 11.Kg5 Kg7 (40)

3/06 0:00 +1.28 10...d5 11.Kg5 d4 12.Kf4 Kg7 (122)

4/08 0:00 +1.22 10...d5 11.Kg5 Kg7 12.Kf4 Kf6 (336)

5/10 0:00 +1.41 10...d5 11.Kg5 e5 12.Kf5 d4 13.Ke4 Kg7
14.Kd3 (742)

6/10 0:00 +1.47 10...d5 11.Kg5 e5 12.Kf5 d4 13.Ke4 Kg7
14.Kd3 Kf6 (1.400)

7/12 0:00 +1.59 10...d5 11.Kg5 e5 12.Kf5 d4 13.Ke4 Kg7
14.Kd3 Kf6 15.Ke4 (2.531)

8/14 0:00 +1.73 10...d5 11.Kg5 Kg7 12.Kg4 e5 13.Kf3 Kf6
14.Ke3 Kf5 15.Kd3 (5.328)

9/14 0:00 +1.87 10...d5 11.Kg5 Kg7 12.Kf4 Kf6 13.Ke3 e5
14.Kd3 Kf5 15.Ke3 d4+ 16.Kd3 (8.446)

10/33 0:00 -7.58 10...d5 11.a4 bxa4 12.b5 Kg8 13.b6 Kf8
14.b7 Ke8 15.b8Q+ Kd7 16.Qb7+ Kd6
17.Qb6+ Ke5 18.Qe3+ Kd6 19.Kf6 Kc6
20.Qxe6+ Kc5 21.Qe7+ Kc4 (227.412)

10/33 0:00 +1.73 10...Kg8 11.Kg5 e5 12.Kf5 Kf7 13.Ke4 Ke6
14.Kd3 d5 15.Ke3 Kf5 16.Kd3 (236.620)

11/37 0:01 -7.63 10...Kg8 11.a4 bxa4 12.b5 Kf8 13.b6 Ke8
14.b7 Kd7 15.b8Q d5 16.Qa7+ Kc6
17.Qxa4+ Kd6 18.Qa7 Ke5 19.Qc7+ Ke4
20.Qc2+ Kf4 21.Qd2+ Ke4 22.Qe2+ Kd4 (1.468.267) 1060

12/37 0:01 -7.94 10...Kg8 11.a4 bxa4 12.b5 Kf8 13.b6 Ke8
14.b7 Kd7 15.b8Q Kc6 16.Qe8+ Kd5
17.Qxa4 Kc5 18.Kg5 Kd5 19.Qa5+ Kc6
20.Qc3+ Kd5 21.Qd2+ Ke4 22.Qf4+ Kd5 (1.655.121) 1056

13/47 0:03 -9.72 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 Kd7
14.a7 Kc7 15.a8Q Kb6 16.Kg5 Kc7
17.Kf6 e5 18.Qa7+ Kc8 19.Qe7 e4
20.Qxd6 e3 21.Qc5+ Kd7 22.Qxb5+ Kd8
23.Qd3+ Ke8 (3.556.983) 1026

14/47 0:03 -10.00 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 Kd7
14.a7 Kc7 15.a8Q Kb6 16.Kf6 e5
17.Kf5 Kc7 18.Qa7+ Kc8 19.Qe7 Kb8
20.Qxd6+ Kb7 21.Qd5+ Kb6 22.Qc5+ Kb7
23.Qxb5+ Kc7 (3.613.498) 1002

15/49 0:04 -10.52 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 Kd7
14.a7 Kc7 15.a8Q Kb6 16.Qb8+ Kc6
17.Qe8+ Kc7 18.Qxe6 Kc6 19.Qxd6+ Kb7
20.Qd7+ Kb8 21.Kf6 Ka8 22.Ke5 (4.418.723) 997

16/55 0:09 -16.53 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 Kd7
14.a7 Kc7 15.a8Q Kb6 16.Qb8+ Kc6
17.Qe8+ Kc7 18.Qxe6 Kc6 19.Qe8+ Kd5
20.Qxb5+ Ke4 21.Qc6+ Ke3 22.Qxd6 Ke2
23.Kf6 Ke3 (9.392.877) 990

17/55 0:23 -M15 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 d5
14.a7 Kd6 15.a8Q Ke5 16.Qc6 d4
17.Qxb5+ Ke4 18.Qc4 Kf3 19.Qxd4 e5
20.Qxe5 Kf2 21.b5 Kf3 22.b6 Kg4
23.Qe3 Kh4 (24.486.596) 1032

18/55 0:27 -M14 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 d5
14.a7 Kd6 15.a8Q Ke5 16.Qc6 d4
17.Qxb5+ Ke4 18.Qe2+ Kf4 19.Qxe6 Kf3
20.Qe2+ Kg3 21.Kf6 Kh3 22.Qg2+ Kh4
23.Kf5 d3 (27.867.931) 1026

19/55 0:35 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 Kd8
14.a7 Kc7 15.a8Q Kb6 16.Kf6 e5
17.Ke6 Kc7 18.Qa7+ Kc6 19.Qd7+ Kb6
20.Kxd6 e4 21.Qc6+ Ka7 22.Kc7 e3
23.Qb7+ (37.111.591) 1040

20/55 0:46 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (48.462.095) 1050

21/55 0:52 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (56.295.805) 1072

22/55 1:01 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (67.348.780) 1098

23/55 1:11 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (80.916.905) 1131

24/55 1:22 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (95.721.642) 1162

25/55 1:34 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (112.614.441) 1196

26/55 1:47 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (132.130.900) 1231

27/55 2:03 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (157.129.912) 1273

28/55 2:19 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (183.674.115) 1313

29/55 2:37 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (214.422.206) 1356

30/55 2:57 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (248.484.991) 1401

31/55 3:17 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (285.355.496) 1442

32/55 3:39 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (325.257.397) 1481

33/55 4:01 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (365.202.530) 1514

34/55 4:23 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (406.166.829) 1544

35/55 4:45 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (447.302.880) 1568

36/55 5:07 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (488.404.990) 1589

37/55 5:28 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (529.150.380) 1608

38/55 5:50 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (570.295.724) 1625

39/55 6:12 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (611.137.242) 1640

40/55 6:34 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (652.135.900) 1653

41/55 6:55 -M13 10...Kg8 11.a4 Kf8 12.a5 Ke7 13.a6 e5
14.a7 e4 15.a8Q e3 16.Qa7+ Ke6
17.Qxe3+ Kd5 18.Kf5 Kc6 19.Ke6 Kc7
20.Kd5 Kd7 21.Qa7+ Ke8 22.Ke6 Kf8
23.Qf7+ (692.902.236) 1665

best move: Kh8-g8 time: 7:00.453 min n/s: 1.668.102 CPU 100.0% n/s(1CPU): 1.668.102 nodes: 701.020.000

Is it really mate in 13 or is Chess Tiger again making the better call with mate in 9 or 10 one ply later in that variation

Eelco

[F.Huber]

Is it really mate in 13 or is Chess Tiger again making the better call with mate in 9 or 10 one ply later in that variation

Well, both engines are wrong here - there´s no #13, not even upto #15 (says ChestUCI).

But after both 1... d5 or 1... e5 (instead of 1... Kg8), #14 with 2.a4 would be possible.

[Eelco de Groot]

Is it really mate in 13 or is Chess Tiger again making the better call with mate in 9 or 10 one ply later in that variation

Well, both engines are wrong here - there´s no #13, not even upto #15 (says ChestUCI).

But after both 1... d5 or 1... e5 (instead of 1... Kg8), #14 with 2.a4 would be possible.

Thanks very much for trying this with Chest Franz! Yes, I came to conclusion that both those analyses were wrong but I do think there must be a longer mate and 10... Kg8 seems best?

The best analysis I have now, at least the one that seems most trustworthy is from Gandalf 6:


Gandalf 6 na 10. Kg6


00:00:00.2 3,32 7 3172 e5 Kf5 Kg7 Ke4 Kf6 Kd5 Kf5
00:00:00.2 3,32 7 4098 d5 Kf6
00:00:00.2 3,61 7 4945 d5 Kg5
00:00:00.3 3,77 7 6262 d5 Kg5 Kg7 Kg4 Kg6 Kf3 Kf5
00:00:00.3 3,00 8 9122 d5 Kg5 Kg7 Kg4 Kg6 Kf3 Kf5
00:00:00.3 2,24 8 9382 d5 Kg5 Kg7 Kg4 Kg6 Kf3 Kf5
00:00:00.3 0,70 8 10795 d5 Kg5 Kg7 Kg4 Kg6 Kf3 Kf5
00:00:00.3 -1,15 9 11110 d5 Kg5 Kg7 Kg4 Kg6 Kf3 Kf5
00:00:00.3 -3,00 9 11421 d5 Kg5 Kg7 Kg4 Kg6 Kf3 Kf5
00:00:00.4 -5,50 9 14119 d5 a4 bxa4 b5 Kg8 b6 Kf8 b7 Ke7 b8Q
00:00:00.4 -5,50 9 14985 Kg8 a4
00:00:00.4 -5,44 9 16791 Kg8 a4 bxa4 b5 a3 b6 Kf8 b7 Ke7 b8Q
00:00:00.4 -5,37 10 20216 Kg8 a4 bxa4 b5 e5 b6 Kf8 b7 Ke7 Kf5 a3 b8Q
00:00:00.4 -5,95 11 21677 Kg8 a4 bxa4 b5 e5 b6 Kf8 b7 Ke7 Kf5 a3 b8Q
00:00:00.4 -6,52 11 23920 Kg8 a4 bxa4 b5 e5 b6 Kf8 b7 Ke7 Kf5 a3 b8Q
00:00:00.5 -7,00 11 32371 Kg8 a4 bxa4 b5 e5 b6 Kf8 b7 Ke7 b8Q Ke6 Qe8+ Kd5 Qa8+ Kd4 Qxa4+ Ke3
00:00:00.5 -6,91 12 45374 Kg8 a4 bxa4 b5 d5 b6 Kf8 b7 Ke8 b8Q+ Kd7 Qa7+ Kd6 Qxa4 e5
00:00:00.6 -7,20 13 76987 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Qe8+ Kc5 Qxa4 d5
00:00:00.8 -7,29 14 113378 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Qe8+ Kc5 Qxa4 d5 Kf6
00:00:01.2 -7,48 15 190076 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Qe8+ Kc5 Qxa4 d5 Kf6 Kd6
00:00:01.7 -7,68 16 373845 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Qe8+ Kd5 Qb5+ Kd4 Qxa4+ Ke5 Qa1+ Ke4 Qe1+ Kd5 Kf6
00:00:03.6 -7,77 17 945209 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Qe8+ Kd5 Qb5+ Kd4 Qxa4+ Kd5 Qa5+ Kd4 Qb6+
00:00:04.0 -8,51 18 1140158 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Qe8+ Kd5 Qb5+ Kd4 Qxa4+ Kd5 Qa5+ Kd4 Qb6+
00:00:04.7 -9,24 18 1587911 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Qe8+ Kd5 Qb5+ Kd4 Qxa4+ Kd5 Qa5+ Kd4 Qb6+
00:00:06.9 -9,53 18 3650425 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Qa8+ Kc5 Qa5+ Kc6 Qxa4+ Kc7 Kf6 e5 Ke6 Kb8 Qb4+ Kc8 Qxd6
00:00:09.8 -11,16 19 4329149 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Qa8+ Kc5 Qa5+ Kc6 Qxa4+ Kc7 Kf6 e5 Ke6 Kb8 Qb4+ Kc8 Qxd6
00:00:10.2 -12,80 19 4448325 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Qa8+ Kc5 Qa5+ Kc6 Qxa4+ Kc7 Kf6 e5 Ke6 Kb8 Qb4+ Kc8 Qxd6
00:00:10.3 -16,06 19 4494291 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Qa8+ Kc5 Qa5+ Kc6 Qxa4+ Kc7 Kf6 e5 Ke6 Kb8 Qb4+ Kc8 Qxd6
00:00:44.8 -20,41 20 27431321 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Qa8+ Kc5 Qa5+ Kc6 Qxa4+ Kc7 Kf6 e5 Ke6 Kb8 Qb4+ Kc8 Qxd6
00:00:46.9 -65,13 20 29170136 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Qa8+ Kc5 Qa5+ Kc6 Qxa4+ Kc7 Kf6 e5 Ke6 Kb8 Qb4+ Kc8 Qxd6
00:02:27.0 -Mate in 18 20 168968956 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Kf6 Kd5 Qa8+ Kc4 Qxa4+ Kd5 Qa5+ Kc4 Kxe6#
00:03:14.4 -Mate in 18 21 231339151 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Kf6 Kd5 Qa8+ Kc4 Qxa4+ Kd5 Qa5+ Kc4 Kxe6#
00:05:06.1 -Mate in 18 22 387109027 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Kf6 Kd5 Qa8+ Kc4 Qxa4+ Kd5 Qa5+ Kc4 Kxe6#
00:08:18.2 -Mate in 18 23 629205365 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Kf6 Kd5 Qa8+ Kc4 Qxa4+ Kd5 Qa5+ Kc4 Kxe6#
00:14:49.4 -Mate in 18 24 1026422985 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Kf6 Kd5 Qa8+ Kc4 Qxa4+ Kd5 Qa5+ Kc4 Kxe6#
00:32:09.0 -Mate in 18 25 1958203953 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Kf6 Kd5 Qa8+ Kc4 Qxa4+ Kd5 Qa5+ Kc4 Kxe6#
01:08:15.9 -Mate in 18 26 3886137705 Kg8 a4 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Kf6 Kd5 Qa8+ Kc4 Qxa4+ Kd5 Qa5+ Kc4 Kxe6#


After 10... Kg8 11. a4 two best moves

Black to move

FEN: [d]6k1/8/3pp1K1/1p6/PP6/8/8/8 b - - 0 1


00:17:24.1 -Mate in 17 22 1170275816 bxa4 b5 Kf8 b6 Ke7 b7 Kd7 b8Q Kc6 Kf6 Kd5 Qa8+ Kc4 Qxa4+ Kd5 Qa5+ Kc4 Kxe6#
00:15:05.6 -Mate in 14 21 979853766 Kf8 a5 Ke7 a6 e5 a7 e4 a8Q e3 Qb7+ Ke6 Qe4+ Kd7 Qxe3 d5 Qb6 d4 Kf6 d3 Ke5 d2 Qb7+ Kd8 Ke6 d1Q Qb8#

With Build 32 I now somehow seem to have nondeterministic PVs but the analysis is a little better, although Toga 1.5 Checkov Build 32 (previous one was actually build No.31 not 30 ,but that is just a small detail) thinks it is mate in 17... Settings here in test 2 with all pruning options switched off. I will post some more later hope to improve this a bit....

Regards, Eelco


[d]7k/8/3pp3/1p4K1/1P6/P7/8/8 w - -

Engine: Toga 1.5 Checkov_beta1 test 2 (256 MB)
by Letouzey, Gaksch, Pudas and de Groot

1/02 0:00 -3.47 10.a4 bxa4 (3)

1/03 0:00 -0.46 10.Kf4 (9)

2/03 0:00 -0.76 10.Kf4 Kg7 (24)

2/05 0:00 -0.58 10.Kf6 e5 11.Kf5 (95)

3/05 0:00 -0.89 10.Kf6 e5 11.Kf5 Kg7 (142)

4/07 0:00 -0.95 10.Kf6 e5 11.Kf5 Kg7 12.Ke4 (353)

5/10 0:00 -0.99 10.Kf6 e5 11.Kf5 Kg7 12.Ke4 Kf6 (768)

6/10 0:00 -1.33 10.Kf6 d5 11.Ke5 Kg7 12.Kd4 Kf6
13.Ke3 (1.662)

6/12 0:00 -1.21 10.Kg4 Kg7 11.Kf4 Kf6 12.Ke4 e5
13.Kd5 (2.637)

7/23 0:00 -1.39 10.Kg4 d5 11.Kf4 d4 12.Ke4 e5 13.Kd3 Kg7
14.Ke4 Kf6 (5.319)

7/23 0:00 -1.01 10.Kf6 e5 11.Kf5 Kg7 12.Ke4 Kf6
13.Kd5 Kf5 14.Kxd6 (6.321)

8/23 0:00 -1.59 10.Kf6 e5 11.Kf5 Kg7 12.Ke4 Kf6
13.Ke3 d5 14.Kd3 e4+ 15.Kd4 (8.125)

9/27 0:00 -1.73 10.Kf6 e5 11.Kf5 Kg7 12.Ke4 Kf6
13.Kd3 d5 14.Ke3 Kf5 15.Kd3 (17.641)

9/30 0:00 -1.71 10.Kf4 e5+ 11.Ke4 Kg7 12.Kd3 Kf6
13.Ke4 Ke6 14.Ke3 d5 15.Kd3 (40.315)

9/32 0:00 -0.32 10.a4 bxa4 11.b5 a3 12.b6 a2 13.b7 a1Q
14.b8Q+ Kh7 15.Qc7+ Qg7+ 16.Qxg7+ Kxg7
17.Kh5 Kg8 18.Kg5 Kf7 19.Kf4 d5
20.Kg5 Kf8 (362.296)

10/32 0:00 0.00 10.a4 bxa4 11.b5 a3 12.b6 a2 13.b7 a1Q
14.b8Q+ Kh7 15.Qc7+ Qg7+ 16.Qxg7+ Kxg7
17.Kh5 Kg8 18.Kg5 Kg7 (538.883)

11/34 0:01 0.00 10.a4 bxa4 11.b5 a3 12.b6 a2 13.b7 a1Q
14.b8Q+ Kh7 15.Qc7+ Qg7+ 16.Qxg7+ Kxg7
17.Kh5 Kg8 18.Kg5 Kg7 (984.317) 830

11/37 0:02 +7.69 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Qe8+ Kc5 17.Qxa4 d5 18.Qa7+ Kb4
19.Qd4+ Kb5 20.Kg5 (1.769.166) 860

12/37 0:02 +7.68 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kc5 17.Kxe6 d5 18.Qd6+ Kc4
19.Qc7+ Kb4 20.Qe7+ Kc4 (1.793.534) 858

13/37 0:02 +7.82 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 e5 17.Ke6 Kc5 18.Qxd6+ Kc4
19.Qd5+ Kc3 20.Qc5+ Kd3 (1.940.867) 852

14/37 0:02 +7.96 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 e5 17.Ke6 Kc5 18.Qxd6+ Kc4
19.Qd5+ Kc3 20.Qc5+ Kd2 21.Qb4+ Ke2 (2.153.798) 845

15/38 0:04 +9.96 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 e5 17.Ke6 Kc5 18.Qxd6+ Kc4
19.Kxe5 Kb3 20.Qd3+ Kb4 21.Qb1+ Kc5
22.Qc1+ Kb5 23.Qf1+ (3.509.971) 847

16/39 0:05 +9.99 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 e5 17.Ke6 Kc5 18.Qxd6+ Kc4
19.Qxe5 Kb4 20.Qb8+ Kc4 21.Qb2 a3
22.Qxa3 Kd4 23.Qd6+ (5.011.877) 858

17/40 0:10 +10.06 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kc5 17.Qc7+ Kb5 18.Qxd6 Kc4
19.Qxe6+ Kc3 20.Qh3+ Kd2 21.Qg4 Ke1
22.Qxa4 Kd2 23.Qd4+ (9.159.926) 884

18/41 0:21 +10.27 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kc5 17.Kxe6 Kc4 18.Qxd6 Kc3
19.Qc6+ Kd4 20.Qxa4+ Kc5 21.Ke5 Kb6
22.Kd5 Kc7 23.Qa7+ (19.713.943) 918

19/46 1:26 +10.49 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kd5 17.Qa8+ Kd4 18.Qxa4+ Ke3
19.Kxe6 d5 20.Kxd5 Kd3 21.Qd4+ Ke2
22.Ke4 Kf1 23.Qe3 (83.226.662) 957

20/46 1:51 +10.70 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kd5 17.Qa8+ Kd4 18.Qxa4+ Kd5
19.Qb3+ Kd4 20.Kxe6 d5 21.Qb4+ Ke3
22.Ke5 d4 23.Qxd4+ (107.358.454) 966

21/50 3:25 +M18 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kd5 17.Qa8+ Kc4 18.Kxe6 Kb3
19.Qb7+ Kc2 20.Qe4+ Kc1 21.Kd5 a3
22.Qe2 Kb1 23.Kc4 (207.443.955) 1011

22/50 4:32 +M17 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kd5 17.Qa8+ Kc4 18.Kxe6 Kb3
19.Qb7+ Kc2 20.Qe4+ Kc1 21.Qc4+ Kd2
22.Kd5 a3 23.Kd4 (278.628.766) 1021

23/50 5:57 +M17 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kd5 17.Qa8+ Kc4 18.Kxe6 Kb3
19.Qb7+ Kc2 20.Qe4+ Kc1 21.Qc4+ Kd2
22.Kd5 a3 23.Kd4 (370.367.996) 1035

24/50 8:54 +M17 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kd5 17.Qa8+ Kc4 18.Kxe6 Kb3
19.Kd5 a3 20.Kd4 a2 21.Qa5 Kb2
22.Qc3+ Kb1 23.Qb3+ (566.197.845) 1059

25/50 12:42 +M17 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kd5 17.Qa8+ Kc4 18.Kxe6 Kb3
19.Kd5 a3 20.Kd4 a2 21.Qa5 Kb2
22.Qc3+ Kb1 23.Qb3+ (823.733.653) 1080

26/50 19:17 +M17 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kd5 17.Qa8+ Kc4 18.Kxe6 Kb3
19.Kd5 a3 20.Kd4 a2 21.Qa5 Kb2
22.Qc3+ Kb1 23.Qb3+ (1.264.204.526) 1092

27/50 30:37 +M17 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kd5 17.Qa8+ Kc4 18.Kxe6 Kb3
19.Kd5 a3 20.Kd4 a2 21.Qa5 Kb2
22.Qc3+ Kb1 23.Qb3+ (2.020.681.292) 1099

28/50 50:19 +M17 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kd5 17.Qa8+ Kc4 18.Kxe6 Kb3
19.Kd5 a3 20.Kd4 a2 21.Qa5 Kb2
22.Qc3+ Kb1 23.Qb3+ (3.345.196.596) 1107

29/50 77:36 +M17 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kd5 17.Qa8+ Kc4 18.Qxa4+ Kd5
19.Qb4 e5 20.Kf5 Kc6 21.Ke6 e4
22.Qc4+ Kb6 23.Kxd6 (5.247.409.538) 1126

30/50 112:32 +M17 10.Kg6 Kg8 11.a4 bxa4 12.b5 Kf8
13.b6 Ke7 14.b7 Kd7 15.b8Q Kc6
16.Kf6 Kd5 17.Qa8+ Kc4 18.Qxa4+ Kd5
19.Qb4 e5 20.Kf5 Kc6 21.Ke6 e4
22.Qc4+ Kb6 23.Kxd6 (7.766.929.056) 1150

best move: Kg5-g6 time: 143:40.016 min n/s: 1.161.010 CPU 100.0% n/s(1CPU): 1.161.010 nodes: 10.007.710.000

[Jouni]

Yes mate in 17x as Fruit shows and Chest confirms:

Fruit-051103:
23/42 02:04 98.784.442 807.270 +M17 a3a4 b5xa4 b4b5 Kg8f8 b5b6 Kf8e7 b6b7 Ke7d7 b7b8Q Kd7c6 Kg6f6 Kc6d5 Qb8b5+ Kd5e4 Qb5xa4+ Ke4d5 Qa4b5+ Kd5e4 Kf6xe6



ChestUCI:

Mate in 17 found ! (1 Solution in 03:58)
17/17 05:16 21.372.878 356.952 +M17 a3a4 b5xa4 b4b5 Kg8f8 b5b6 Kf8e8 b6b7 Ke8d7 b7b8Q Kd7c6 Qb8e8+ Kc6b6 Qe8xa4 Kb6c5 Qa4a3+ Kc5d5 Kg6f6 e6e5 Qa3d3+ Kd5c5 Kf6e6 Kc5b4 Qd3c2 e5e4 Ke6xd6 e4e3 Kd6d5 e3e2 Qc2b2+ Kb4a4 Kd5c5 e2e1Q Qb2a2+

Jouni