Mate in ?

JVMerlino · Post by **JVMerlino** » Thu Dec 01, 2022 6:18 am

[fen]8/8/8/4b1k1/8/5P2/Pp5p/1K5R w - -[/fen]

I've made what I thought are some small adjustments to Myrddin's hash replacement scheme and now it is getting some results in deep test positions that it never got before. For example, in the above, Myrddin is finally able to announce mate (in this case, mate in 31, although it still takes 5 minutes with four cores).

Can somebody confirm for me what the shortest mate is? Thank you!

jm

p.s. Myrddin 0.90 release will be soon, and it will support Chess960.

Joost Buijs · Post by **Joost Buijs** » Thu Dec 01, 2022 5:07 pm

Mate in 31 is correct, Nightmare without EGDB does not find it in a reasonable time, with 6P Nalimov EGDB it sees the mate in 31 in 0.3 sec.

JVMerlino · Post by **JVMerlino** » Thu Dec 01, 2022 5:30 pm

Wow, rather shocking that Myrddin got it right. Thanks, Joost!

Vinvin · Post by **Vinvin** » Thu Dec 01, 2022 7:36 pm

The Huntsman 1 confirms after 1h40m AMD 5950x 16 threads.

FEN: 8/8/8/4b1k1/8/5P2/Pp5p/1K5R w - - 0 1
The Huntsman 1 avx2:
classical evaluation enabled
...
89/64 11:24 35.023.156k 51.139k +M32 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Qa4+ Kf5 11.Qc4 Kf6 12.Qg4 Ke7 13.Qf5 Kd6 14.Ka2 Kd5 15.Kb3 Kd6 16.Kc4 Bh8 17.Qe4 Bf6 18.Qd5+ Ke7 19.Qf5 b1Q 20.Qxb1 Ke6 21.Qe1+ Kd6 22.Qa5 Bg7 23.Qb6+ Ke5 24.Qb2+ Ke6 25.Qxg7 Kf5 26.Kd5 Kf4 27.Qc3 Kf5 28.Qf3+ Kg6 29.Ke6 Kg5 30.Qg3+ Kh6 31.Kf6 Kh5 32.Qh3+
90/66 14:16 45.276.011k 52.849k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb5 Kf7 21.Kd3 Ke6 22.Ke4 Kd6 23.Qd5+ Ke7 24.Kf5 Bc3 25.Qe6+ Kd8 26.Qc6 Ke7 27.Qc7+ Kf8 28.Qd8+ Kg7 29.Qd7+ Kg8 30.Kg6 Kf8 31.Qd8+
91/62 19:49 64.596.696k 54.316k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb5 Kf7 21.Kd3 Ke6 22.Ke4 Kd6 23.Qd5+ Ke7 24.Kf5 Bc3 25.Qe6+ Kd8 26.Qc6 Ke7 27.Qc7+ Kf8 28.Qd8+ Kg7 29.Qd7+ Kg8 30.Kg6 Kf8 31.Qd8+
92/62 1:18:57 283.342.663k 59.808k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb5 Kf6 21.Kd3 Ke6 22.Ke4 Kd6 23.Qd5+ Ke7 24.Kf5 Bc3 25.Qe6+ Kd8 26.Qc6 Ke7 27.Qc7+ Kf8 28.Qd8+ Kg7 29.Qd7+ Kg8 30.Kg6 Kf8 31.Qd8+
93/72 1:19:07 283.898.428k 59.802k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
94/62 1:19:10 284.087.165k 59.800k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
95/62 1:19:12 284.214.329k 59.800k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
96/62 1:19:15 284.345.791k 59.799k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
97/62 1:19:19 284.605.726k 59.797k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
98/62 1:19:23 284.868.493k 59.796k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
99/62 1:19:27 285.060.354k 59.794k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
100/62 1:19:37 285.610.463k 59.784k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
101/62 1:19:43 285.948.345k 59.778k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
102/62 1:19:52 286.462.440k 59.774k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
103/62 1:19:55 286.668.839k 59.775k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
104/62 1:20:20 288.131.668k 59.770k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
105/62 1:23:08 297.509.905k 59.643k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
106/62 1:40:12 360.041.410k 59.881k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bb2 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kd5 Kh7 28.Ke6 Bd8 29.Kf7 Bg5 30.Qxg5 Kh8 31.Qh5+

Chessnut1071 · Post by **Chessnut1071** » Fri Dec 02, 2022 6:36 am

Vinvin wrote: ↑Thu Dec 01, 2022 7:36 pm The Huntsman 1 confirms after 1h40m AMD 5950x 16 threads.

FEN: 8/8/8/4b1k1/8/5P2/Pp5p/1K5R w - - 0 1
The Huntsman 1 avx2:
classical evaluation enabled
...
89/64 11:24 35.023.156k 51.139k +M32 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Qa4+ Kf5 11.Qc4 Kf6 12.Qg4 Ke7 13.Qf5 Kd6 14.Ka2 Kd5 15.Kb3 Kd6 16.Kc4 Bh8 17.Qe4 Bf6 18.Qd5+ Ke7 19.Qf5 b1Q 20.Qxb1 Ke6 21.Qe1+ Kd6 22.Qa5 Bg7 23.Qb6+ Ke5 24.Qb2+ Ke6 25.Qxg7 Kf5 26.Kd5 Kf4 27.Qc3 Kf5 28.Qf3+ Kg6 29.Ke6 Kg5 30.Qg3+ Kh6 31.Kf6 Kh5 32.Qh3+
90/66 14:16 45.276.011k 52.849k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb5 Kf7 21.Kd3 Ke6 22.Ke4 Kd6 23.Qd5+ Ke7 24.Kf5 Bc3 25.Qe6+ Kd8 26.Qc6 Ke7 27.Qc7+ Kf8 28.Qd8+ Kg7 29.Qd7+ Kg8 30.Kg6 Kf8 31.Qd8+
91/62 19:49 64.596.696k 54.316k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb5 Kf7 21.Kd3 Ke6 22.Ke4 Kd6 23.Qd5+ Ke7 24.Kf5 Bc3 25.Qe6+ Kd8 26.Qc6 Ke7 27.Qc7+ Kf8 28.Qd8+ Kg7 29.Qd7+ Kg8 30.Kg6 Kf8 31.Qd8+
92/62 1:18:57 283.342.663k 59.808k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb5 Kf6 21.Kd3 Ke6 22.Ke4 Kd6 23.Qd5+ Ke7 24.Kf5 Bc3 25.Qe6+ Kd8 26.Qc6 Ke7 27.Qc7+ Kf8 28.Qd8+ Kg7 29.Qd7+ Kg8 30.Kg6 Kf8 31.Qd8+
93/72 1:19:07 283.898.428k 59.802k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
94/62 1:19:10 284.087.165k 59.800k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
95/62 1:19:12 284.214.329k 59.800k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
96/62 1:19:15 284.345.791k 59.799k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
97/62 1:19:19 284.605.726k 59.797k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
98/62 1:19:23 284.868.493k 59.796k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
99/62 1:19:27 285.060.354k 59.794k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
100/62 1:19:37 285.610.463k 59.784k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
101/62 1:19:43 285.948.345k 59.778k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
102/62 1:19:52 286.462.440k 59.774k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
103/62 1:19:55 286.668.839k 59.775k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
104/62 1:20:20 288.131.668k 59.770k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
105/62 1:23:08 297.509.905k 59.643k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bg7 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kf5 Kh7 28.Qg6+ Kh8 29.Kf6 Bc3+ 30.Kf7 Bb2 31.Qh5+
106/62 1:40:12 360.041.410k 59.881k +M31 1.a4 Kh4 2.a5 Kh3 3.a6 Bd4 4.f4 Kg2 5.Rxh2+ Kxh2 6.f5 Kg3 7.f6 Bxf6 8.a7 Be5 9.a8Q Kf4 10.Kc2 Kf5 11.Qd5 Kf6 12.Qd7 Kg5 13.Qf7 Bf6 14.Qe6 Kg6 15.Qg4+ Kf7 16.Qf5 Ke7 17.Qd5 Bg7 18.Qb7+ Kf6 19.Qxb2+ Kg6 20.Qb7 Bf6 21.Kd3 Kf5 22.Qe4+ Kg5 23.Qe6 Bb2 24.Ke4 Bc3 25.Qf5+ Kh6 26.Qg4 Ba5 27.Kd5 Kh7 28.Ke6 Bd8 29.Kf7 Bg5 30.Qxg5 Kh8 31.Qh5+

Interesting how easy it is to see 1. a4 leads to forced mate by visual inspection, you must advance the queen's pawn because nothing else works. However, the computer needs to brute force the solution taking trillions of moves. I guess this is a case where the computer is inferior to the human intellect. I couldn't do it in 31 moves, however, it took me 39 moves and over 5 hours, but, I'm only 2045 OTB. A human grandmaster should be able to solve this in under 1 hour. Once I started computer chess programming, I lost my desire to play OTB. Did that happen to the rest of you too?

JVMerlino · Post by **JVMerlino** » Fri Dec 02, 2022 5:56 pm

Chessnut1071 wrote: ↑Fri Dec 02, 2022 6:36 am Interesting how easy it is to see 1. a4 leads to forced mate by visual inspection, you must advance the queen's pawn because nothing else works. However, the computer needs to brute force the solution taking trillions of moves. I guess this is a case where the computer is inferior to the human intellect. I couldn't do it in 31 moves, however, it took me 39 moves and over 5 hours, but, I'm only 2045 OTB. A human grandmaster should be able to solve this in under 1 hour. Once I started computer chess programming, I lost my desire to play OTB. Did that happen to the rest of you too?

Definitely not "brute force", of course. That's the magic of alpha-beta, reductions, pruning, EGTBs, etc. Turning something that would take trillions (or more!) nodes into, in Myrddin's case, about 2.4 billion nodes to solve.

hgm · Post by **hgm** » Fri Dec 02, 2022 6:41 pm

Trivial to solve, in a few seconds, right? The a-Pawn has only 8 locations without capturing the Bishop, the f-Pawn, only 7 (counting 8th rank and absence), for a total of 56 Pawn structures. (The black Pawns should never be allowed to advance safely.) Times 4 moving pieces. Less work than a 5-men EGT.

Chessnut1071 · Post by **Chessnut1071** » Fri Dec 02, 2022 10:23 pm

hgm wrote: ↑Fri Dec 02, 2022 6:41 pm Trivial to solve, in a few seconds, right? The a-Pawn has only 8 locations without capturing the Bishop, the f-Pawn, only 7 (counting 8th rank and absence), for a total of 56 Pawn structures. (The black Pawns should never be allowed to advance safely.) Times 4 moving pieces. Less work than a 5-men EGT.

Visual inspection can deduce that; however, programming a generic solution for a range of problems and which includes the above mate is tremendous task. It's fairly easy to program a specific solution to the above problem once you see the mating sequence. That's why I like problems like this to also supply the evaluation function; otherwise, I assume the super-fast solutions were specific rather than generic. I guarantee, alpha/beta is not enough to solve the above mate without a super-efficient evaluation.

hgm · Post by **hgm** » Fri Dec 02, 2022 10:30 pm

Not really. You just use an EGT generator. Which is a quite simple, very generic program, which would solve all positions of this kind (4 men plus some Pawns). No evaluation needed at all.

Uri Blass · Post by **Uri Blass** » Sat Dec 03, 2022 1:03 am

hgm wrote: ↑Fri Dec 02, 2022 6:41 pm Trivial to solve, in a few seconds, right? The a-Pawn has only 8 locations without capturing the Bishop, the f-Pawn, only 7 (counting 8th rank and absence), for a total of 56 Pawn structures. (The black Pawns should never be allowed to advance safely.) Times 4 moving pieces. Less work than a 5-men EGT.

I do not understand
If you want to find distance to mate and you generate tablebases then you cannot count 8th rank as one position because a queen that you promote can be later in many possible squares.

basically future interesting positions include all KQRKB structures with pawn at f3 and black pawn in b2 or not and in f2 or not.
It is clearly more work then 5-men EGT

Mate in ?

Mate in ?

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