Is it mate in 11 and is e4 the only solution?

[Uri Blass]

https://www.stmintz.com/ccc/index.php?id=303412

I wonder what is verified by chest.

Heiner Marxen verified many years ago no mate in 9 in 2003 and I wonder if no mate in 10 is verified by chest and if 1.e4 is the only solution for mate in 11.

In 2003 Heiner needed one hour for chest to prove no mate in 9.
I wonder how much hardware improvement from 2003 from that time for single core engines and how much time does chest need today(I guess that I do not have top hardware for using one core so my time to prove no mate in 9 means nothing).

Chest is also free source code and I wonder if somebody can change the code to use more hash because today the maximal hash it can use is 2048 mbytes.
[fen]3qk3/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1 [/fen]

[Uri Blass]

I can add that when I give it for chest I read
FEN: 3qk3/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1

ChestUCI:
FEN: 3qk3/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - (16+2)
Stellungs-Analyse: C0/R0/K5/P2/X20 W:10/20
Problem in Datenbank gefunden: #11;
Suche nach Matt in 126 ... (Hash=2044MB)

I do not know what is the meaning of Datenbank gefunden and I do not know if it only means that there is mate in 11 and no mate in 10 or also that chest found all the possible solutions for mate in 11.

[Ajedrecista]

Hello Uri:

'Datenbank gefunden' means 'Found in database. You should read this thread:

Initial position -x pieces for black

Where some people tried to solve the position. There was an user who ran Houdini 6 and reported both 1.- e4 and 1.- Nc3 as checkmate in 11 moves. I tried Chest 5.2 in normal mode and realised that the full search would have taken a lot of hours in my PC given the time that shallower depths took.

Regards from Spain.

Ajedrecista.

[Jouni]

Old favorite again

Analysis by Stockfish 060921:

1. +- (#11): 1.e4 Qd4 2.Qg4 Ke7 3.Nc3 Kf8 4.Nf3 Qg7 5.Qc8+ Ke7 6.d4 Qg6 7.Bg5+ Qxg5 8.Nxg5 Kf6 9.Qe6+ Kg7 10.Bc4 Kh8 11.Qh6#
2. +- (#12): 1.d4 Qa5+ 2.Nc3 Qh5 3.e4 Qg6 4.Qf3 Qf7 5.Qg4 Kf8 6.Bh6+ Ke7 7.Nd5+ Kd6 8.Bf4+ Qxf4 9.Qxf4+ Ke6 10.Qf6+ Kd7 11.Qe7+ Kc8 12.Qc7#
3. +- (#12): 1.Nc3 Qg5 2.e3 Kf7 3.Qf3+ Kg7 4.h4 Qg6 5.h5 Qf7 6.Qxf7+ Kxf7 7.h6 Ke7 8.h7 Kd7 9.h8Q Kc7 10.Rh6 Kd7 11.Qg7+ Ke8 12.Rh8#
4. +- (#12): 1.e3 Qc7 2.Nc3 Kf8 3.Qf3+ Kg8 4.h4 Qf7 5.h5 Qxf3 6.Nxf3 Kh7 7.h6 Kg8 8.h7+ Kf7 9.h8Q Ke7 10.Rh7+ Kd6 11.Qe5+ Kc6 12.Qc7#
5. +- (#12): 1.h4 Qf6 2.h5 Qh6 3.e3 Ke7 4.Qg4 Qh7 5.Qb4+ Kd8 6.Qb8+ Kd7 7.Qb7+ Kd6 8.Qxh7 Kc6 9.d4 Kd6 10.Bb5 Ke6 11.Qg7 Kd6 12.Qe5#
6. +- (#12): 1.a4 Qa5 2.e4 Kf7 3.Qf3+ Kg7 4.Qc3+ Qxc3 5.Nxc3 Kh7 6.a5 Kg8 7.a6 Kf8 8.a7 Kf7 9.Ra6 Ke7 10.a8Q Kf7 11.Qb7+ Kf8 12.Ra8#
7. +- (#12): 1.b3 Kd7 2.e3 Kc7 3.Nc3 Qa8 4.Qg4 Kb8 5.Nb5 Qb7 6.Ba3 Qh7 7.Nd6 Qc7 8.Qa4 Qxc2 9.Qb5+ Kc7 10.Qb7+ Kd8 11.Nf7+ Ke8 12.Qe7#
8. +- (#13): 1.g3 Qd4 2.e4 Kf8 3.Nc3 Qg7 4.Qf3+ Qf7 5.Qxf7+ Kxf7 6.a4 Ke6 7.a5 Kf6 8.a6 Ke5 9.a7 Kd6 10.Ra6+ Kc7 11.a8Q Kd7 12.Bb5+ Ke7 13.Qe8#
9. +- (#13): 1.Nf3 Kd7 2.e3 Qa5 3.a4 Ke7 4.Nd4 Qb6 5.a5 Qc5 6.Qg4 Ke8 7.a6 Qa7 8.Qc8+ Kf7 9.Bc4+ Kg6 10.Qe6+ Kh7 11.Qg8+ Kh6 12.Nf5+ Kh5 13.Be2#
10. +- (#13): 1.d3 Kf7 2.e4 Qd6 3.Nc3 Qg6 4.Qf3+ Kg8 5.d4 Qe6 6.Bf4 Kh7 7.Qh5+ Kg7 8.Be5+ Kf8 9.Bb5 Qxe5 10.dxe5 Kg8 11.Bc4+ Kg7 12.h4 Kf8 13.Qf7#
11. +- (#13): 1.b4 Kd7 2.e3 Kc7 3.Nc3 Qa8 4.Qg4 Qc8 5.Qxc8+ Kxc8 6.h4 Kb8 7.h5 Ka7 8.h6 Kb7 9.h7 Kc7 10.h8Q Kd6 11.Rh6+ Kc7 12.Rh7+ Kc6 13.Qf6#
12. +- (#13): 1.c3 Qd5 2.Qa4+ Kd8 3.d4 Kc8 4.Qe8+ Qd8 5.Qxd8+ Kxd8 6.h4 Kc7 7.h5 Kd7 8.h6 Ke8 9.h7 Kf8 10.h8Q+ Ke7 11.Qg7+ Ke6 12.e4 Kd6 13.Rh6#
13. +- (#13): 1.Na3 Qh4 2.e3 Ke7 3.Qf3 Qg5 4.Nb5 Qc5 5.Qb7+ Kf6 6.b3 Qxc2 7.Bc4 Kg6 8.Qf7+ Kh6 9.Ba3 Qg6 10.Bf8+ Kh5 11.Be2+ Kh4 12.g3+ Qxg3 13.Qh5#
14. +- (#13): 1.h3 Qh4 2.e4 Qf6 3.Qf3 Qg6 4.d4 Qf7 5.Qxf7+ Kxf7 6.h4 Ke6 7.h5 Ke7 8.h6 Ke6 9.h7 Kd7 10.h8Q Kc7 11.Bf4+ Kb6 12.Qb8+ Kc6 13.Bb5#
15. +- (#13): 1.g4 Ke7 2.e3 Qd7 3.Qf3 Qe6 4.Nc3 Qf7 5.Qxf7+ Kxf7 6.a4 Kf8 7.a5 Kf7 8.a6 Kg6 9.a7 Kg5 10.a8Q Kh6 11.Qb7 Kg6 12.f4 Kh6 13.Ra6#
16. +- (#14): 1.a3 Kf7 2.e3 Qa5 3.a4 Ke8 4.Qf3 Kd7 5.Nc3 Kc8 6.Bb5 Qc7 7.Qa8+ Qb8 8.Ba6+ Kd7 9.Qxb8 Ke7 10.Nd5+ Kf7 11.Qb6 Kg7 12.Qf6+ Kh7 13.Bd3+ Kg8 14.Ne7#
17. +- (#14): 1.c4 Qc7 2.e3 Kf8 3.Nc3 Qd7 4.Qf3+ Kg7 5.Nd5 Qf7 6.Qg3+ Kh8 7.b4 Qg7 8.Qb8+ Kh7 9.Bd3+ Qg6 10.Bb2 Qxd3 11.Qb7+ Kh6 12.Qg7+ Kh5 13.Nf4+ Kh4 14.g3#
18. +- (#14): 1.Nh3 Kd7 2.e3 Kc8 3.a4 Qa5 4.Nc3 Kb8 5.Qg4 Kc7 6.Qe4 Qc5 7.Qe8 Qc6 8.Nb5+ Kb7 9.Qe7+ Kb8 10.Bd3 Qb6 11.Qe8+ Kb7 12.Be4+ Ka6 13.Qa8+ Qa7 14.Qxa7#
19. +- (#14): 1.f4 Qh4+ 2.g3 Qf6 3.e3 Qf5 4.Qf3 Kd8 5.Qa8+ Qc8 6.Qxc8+ Kxc8 7.h4 Kc7 8.h5 Kd6 9.h6 Ke7 10.h7 Kf6 11.h8Q+ Ke7 12.Rh6 Kf7 13.Rh7+ Kg6 14.Bd3#
20. +- (#16): 1.f3 Qh4+ 2.g3 Qc4 3.c3 Qc6 4.Qb3 Kf8 5.Qb8+ Kf7 6.e3 Qc5 7.b3 Qf8 8.Qf4+ Kg8 9.Bc4+ Kg7 10.Qg5+ Kh8 11.Bd3 Qb4 12.Ba3 Qd

[Ignacio]

After 2 h. 44 min. Chest says: No mate in 10.
Best.

Ignacio

[Uri Blass]

After many hours chest could verify that h3 h4 g3 g4 f3 f4 e3 d3 d4 c3 c4 are not mate in 11 when e4 is a real solution.

FEN: 3qk3/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1

ChestUCI:
FEN: 3qk3/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - (16+2)
Stellungs-Analyse: C0/R0/K5/P2/X20 W:10/20
Problem in Datenbank gefunden: #11;
Suche nach Matt in 126 ... (Hash=2044MB)
11 71:08:39 263,354,584k 1,583k +M11 e2-e4

Searched so far 476,894,006,479 nodes and considers b3 at this moment(not sure if I will wait to finish the analysis).

[Uri Blass]

b3 is also no mate and after 503,936,892,980 nodes chest is analyzing b4

[Uri Blass]

b4 is also not mate after 527,690,494,504 nodes

[Uri Blass]

As expected a3 also no mate in 11 after 538,583,914,097 nodes
a4 also no mate in 11 after 565,541,179,782 nodes

Next move to try Nf3

[fishpov]

3qk3/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1

Analysis by Stockfish 250222 :
...
1.e3 Qg5 2.h4 Qf5 3.Qf3 Qxc2 4.Nc3 Qh7 5.Bb5+ Qd7 6.Bxd7+ Kxd7 7.h5 Kc7 8.Nd5+ Kb8 9.Qf7 Ka8 10.Qg8+ Ka7 11.h6 Kb7 12.Qf7+ Kc6 13.Qf6+ Kb5
+- (#18) Depth: 22/29 00:00:04 72349kN
1.e3 Qg5 2.h4 Qf5 3.Qf3 Qxc2 4.Bb5+ Ke7 5.Nc3 Qg6 6.h5 Qe6 7.h6 Kd8 8.Qf8+ Kc7 9.h7 Qe5 10.h8Q Qxh8 11.Rxh8
+- (#14) Depth: 23/31 00:00:05 94985kN
...
1.e3 Qg5 2.h4 Qf5 3.Qf3 Qxc2 4.Nc3 Qg6 5.Bb5+ Ke7 6.h5 Qe6 7.h6 Kd8 8.Qf8+ Kc7 9.h7 Qe5 10.h8Q Kb7 11.Qa8+ Kb6 12.Rh6+ Qd6 13.Rxd6+ Kc7
+- (#14) Depth: 24/26 00:00:05 96341kN
1.e3 Qg5 2.h4 Qf5 3.Qf3 Qxc2 4.Nc3 Qg6 5.Bb5+ Ke7 6.h5 Qe6 7.h6 Kd8 8.Qf8+ Kc7 9.h7 Qe5 10.h8Q Kb7 11.Qa8+ Kb6 12.Rh6+ Qd6 13.Rxd6+ Kc7 14.Qc6#
+- (#14) Depth: 25/27 00:00:06 99738kN
1.e3 Qg5 2.h4 Qf5 3.Qf3 Qxc2 4.Nc3 Qg6 5.h5 Qh6 6.Bb5+ Ke7 7.Qb7+ Kf8 8.Qd7 Qh7 9.Qe8+ Kg7 10.h6+ Kf6 11.Nd5+ Kf5 12.Rh5+ Kg4 13.Nf6#
+- (#13) Depth: 26/28 00:00:06 110MN
1.e3 Qg5 2.h4 Qf5 3.Qf3 Qxc2 4.Nc3 Qg6 5.h5 Qh6 6.Bb5+ Ke7 7.Qb7+ Kf8 8.Qd7 Qh7 9.Qe8+ Kg7 10.h6+ Kf6 11.Nd5+ Kf5 12.Rh5+ Kg4 13.Nf6#
+- (#13) Depth: 27/26 00:00:07 115MN
...
1.e3 Qg5 2.h4 Qh6 3.h5 Kd8 4.Qf3 Kc8 5.Nc3 Kb8 6.Qf4+ Qxf4 7.exf4 Kc7 8.h6 Kc6 9.h7 Kc7 10.Rh6 Kd7 11.h8Q Kc7 12.Qg7+ Kc8 13.Rh8#
+- (#13) Depth: 37/26 00:00:15 238MN
1.e3 Qg5 2.h4 Qh6 3.h5 Kd8 4.Qg4 Ke7 5.Bb5 Qd6 6.h6 Kd8 7.h7 Kc7 8.h8Q Kb6 9.Qhc8 Kxb5 10.Qb7+ Ka5 11.Rh5+ Qd5 12.Rxd5#
+- (#12) Depth: 38/26 00:00:16 252MN
...
1.e3 Qg5 2.h4 Qh6 3.h5 Kd8 4.Qg4 Ke7 5.Bb5 Qd6 6.h6 Kd8 7.h7 Kc7 8.h8Q Kb6 9.Qhc8 Kxb5 10.Qb7+ Ka5 11.Rh5+ Qd5 12.Rxd5#
+- (#12) Depth: 74/24 00:11:05 10974MN
1.e4 Kf8 2.Qf3+ Kg7 3.Qg4+ Kf7 4.b3 Qf6 5.Ba3 Qc6 6.Nf3 Ke8 7.Ne5 Kd8 8.Nxc6+ Kc7 9.Ne7 Kb7 10.Bc5 Ka8 11.Qc8#
+- (#11) Depth: 75/24 00:16:30 17481MN