Difficult mate in 7

[David Dahlem]

[D]rBb5/P2p4/PK1P4/1B1pp3/2prn3/1Rnk1p2/3p1p1p/2bB1N1N w - - 0 1

Can any engine find this mate in 7? ChestUCI found it instantly!!

Chest 5.1:

Mate in 7 found ! (1 Solution in 00:00)
7/7 00:02 73.246 391.689 +M7 Kb6a5 Bc1b2 Ka5b4 Bb2a1 Kb4a3 Bc8b7 a6xb7 Ba1b2+ Ka3xb2 Ra8xb8 Rb3xc3+ Ne4xc3 Nh1xf2+

[acase]

Rybka 3 Dynamic found it rather quickly on my laptop.


New game
rBb5/P2p4/PK1P4/1B1pp3/2prn3/1Rnk1p2/3p1p1p/2bB1N1N w - - 0 1

Analysis by Rybka 3 Dynamic 32-bit:

1.Ka5 Bb2
-+ (-9.19) Depth: 6 00:00:00 4kN
1.Ka5 Bb2 2.Kb4
+- (4.63) Depth: 7 00:00:00 20kN
1.Ka5
+- (4.83 !) Depth: 8 00:00:00 21kN
1.Ka5
+- (5.03 !) Depth: 8 00:00:00 21kN
1.Ka5
+- (5.43 !) Depth: 8 00:00:00 23kN
1.Ka5
+- (6.23 !) Depth: 8 00:00:00 26kN
1.Ka5
+- (7.10) Depth: 8 00:00:01 41kN
1.Ka5
+- (13.10) Depth: 9 00:00:02 115kN
1.Ka5
+- (#9) Depth: 10 00:00:02 146kN
1.Ka5
+- (#7) Depth: 11 00:00:02 200kN
1.Ka5
+- (#7) Depth: 12 00:00:03 265kN
1.Ka5
+- (#7) Depth: 13 00:00:09 1193kN
1.Ka5
+- (#7) Depth: 14 00:01:06 9840kN

[David Dahlem]

Rybka 3 Dynamic found it rather quickly on my laptop.

I just tried Rybka 3 Dynamic, and it took 2 seconds, the first engine other than Chest that finds the mate for me. That's amazing, Rybka 3 Default and Rybka 3 Human don't have a clue.

[kgburcham]

[D] rBb5/P2p4/PK1P4/1B1pp3/2prn3/1Rnk1p2/3p1p1p/2bB1N1N w - - 0 1

Zappa
(null move off)

11/41 0:01 0.00 1.Kc7 Bb2 2.Kb6 Bc1 (5.016.720) 2614
12/43 0:02 0.00 1.Kc7 Bb2 2.Kb6 Bc1 3.Kc7 (7.550.390) 2749
12/43 0:04 0.00 1.Kc7 Bb2 2.Kb6 Bc1 (11.871.292) 2882
13/45 0:06 0.00 1.Kc7 Bb2 2.Kb6 Bc1 3.Kc7 (19.047.310) 2942
13/45 0:09 0.00 1.Kc7 Bb2 2.Kb6 Bc1 (29.874.627) 3020
14/47 0:10 0.00 1.Kc7 Bb2 2.Kb6 Bc1 3.Kc7 (30.846.375) 3005
14/47 0:16 +M7 1.Ka5 Bb2 2.Kb4 Ba1 3.Ka3 Bxa6 4.Bxa6 Rxa7 5.Bxa7 Bb2+ 6.Kxb2 Nxd6 7.Nxf2+ (52.209.678) 3084
14/47 0:19 +M7 1.Ka5 Bb2 2.Kb4 Ba1 3.Ka3 Bxa6 4.Bxa6 Rxa7 5.Bxa7 Bb2+ 6.Kxb2 Nxd6 7.Nxf2+ (59.368.163) 3119
15/49 0:19 +M7 1.Ka5 Bb2 2.Kb4 Ba1 3.Ka3 Bxa6 4.Bxa6 Rxa7 5.Bxa7 Bb2+ 6.Kxb2 Nxd6 7.Nxf2+ (62.442.612) 3134
15/49 0:25 +M7 1.Ka5 Bb2 2.Kb4 Ba1 3.Ka3 Bxa6 4.Bxa6 Rxa7 5.Bxa7 Bb2+ 6.Kxb2 Nxd6 7.Nxf2+ (84.623.179) 3265
16/51 0:27 +M7 1.Ka5 Bb2 2.Kb4 Ba1 3.Ka3 Bxa6

[David Dahlem]

Move the white king one square and it is much more difficult (mate in 8)
[D]rBb5/P1Kp4/P2P4/1B1pp3/2prn3/1Rnk1p2/1b1p1p1p/3B1N1N w - - 0 1

Forget about this (mate in 14)
[D]rBb5/P2p4/P2P3K/1B1pp3/2prn3/1Rnk1p2/1b1p1p1p/3B1N1N w - - 0 1

Chest has no problem solving these.