White to move and force mate in 81

[peter]

Yes.

Edited my last posting after your answer, Gustav's a great program, isn't it, regards

[acase]

Try to solve this puzzle[/size]

K7/p3p1p1/1p2p1p1/rp4B1/brpn4/Rnk5/8/4N1N1 w

Actually Gustav CAN solve this mate, see here:

https://www.chessprogramming.org/Gustav#Longest_Problem

The longest for Gustav solvable problem so far has 163 moves, not in 163 moves, I believe that the shortest amount that this puzzle can be solved is 167 moves, which is correct

Well it DOES look like Gustav can solve this in 163 moves which means it found a shorter mate as Peter has pointed out

[peter]

Yes.

Olaf Jenkner, the author of Gustav, having seen this thread too, sent me an email writing he had increased the number of moves to mate for the development version of the program to 210 and thus got the full solution to the longer one Blathy- study, of which you brought the position after 40 moves (HHdbVI nr. 0798.38a3d3).
Here's Gustav's main variant:
[fen]rBb5/P2p4/P2Ppp1p/1B1p1p1B/2prn3/KRnk4/3p4/b4N1N w - - 0 1[/fen]

Code: Select all

1.Bh5-d1 Bh6-h5 2.Ka3-b4 La1-b2 3.Kb4-a5 Lb2-c1 4.Ka5-b6 Lc1-b2 5.Kb6-c7 Lb2-c1 6.Kc7-d8 Lc1-b2 7.Kd8-e7 Lb2-c1 8.Ke7-f8 Lc1-b2 9.Kf8-g7 Lb2-c1 10.Kg7-g8 Lc1-b2 11.Kg8-f8 Lb2-c1 12.Kf8-e7 Lc1-b2 13.Ke7-d8 Lb2-c1 14.Kd8-c7 Lc1-b2 15.Kc7-b6 Lb2-c1 16.Kb6-a5 Lc1-b2 17.Ka5-b4 Lb2-a1 18.Kb4-a3 Bf5-f4 19.Ka3-b4 La1-b2 20.Kb4-a5 Lb2-c1 21.Ka5-b6 Lc1-b2 22.Kb6-c7 Lb2-c1 23.Kc7-d8 Lc1-b2 24.Kd8-e7 Lb2-c1 25.Ke7-f8 Lc1-b2 26.Kf8-g7 Lb2-c1 27.Kg7-g8 Lc1-b2 28.Kg8-f8 Lb2-c1 29.Kf8-e7 Lc1-b2 30.Ke7-d8 Lb2-c1 31.Kd8-c7 Lc1-b2 32.Kc7-b6 Lb2-c1 33.Kb6-a5 Lc1-b2 34.Ka5-b4 Lb2-a1 35.Kb4-a3 Bf6-f5 36.Ka3-b4 La1-b2 37.Kb4-a5 Lb2-c1 38.Ka5-b6 Lc1-b2 39.Kb6-c7 Lb2-c1 40.Kc7-d8 Lc1-b2 41.Kd8-e7 Lb2-c1 42.Ke7-f8 Lc1-b2 43.Kf8-g7 Lb2-c1 44.Kg7-g6 Lc1-b2 45.Kg6-h6 Lb2-c1 46.Kh6-g7 Lc1-b2 47.Kg7-f8 Lb2-c1 48.Kf8-e7 Lc1-b2 49.Ke7-d8 Lb2-c1 50.Kd8-c7 Lc1-b2 51.Kc7-b6 Lb2-c1 52.Kb6-a5 Lc1-b2 53.Ka5-b4 Lb2-a1 54.Kb4-a3 Bf4-f3 55.Ka3-b4 La1-b2 56.Kb4-a5 Lb2-c1 57.Ka5-b6 Lc1-b2 58.Kb6-c7 Lb2-c1 59.Kc7-d8 Lc1-b2 60.Kd8-e7 Lb2-c1 61.Ke7-f8 Lc1-b2 62.Kf8-g7 Lb2-c1 63.Kg7-g6 Lc1-b2 64.Kg6-h6 Lb2-c1 65.Kh6-g7 Lc1-b2 66.Kg7-f8 Lb2-c1 67.Kf8-e7 Lc1-b2 68.Ke7-d8 Lb2-c1 69.Kd8-c7 Lc1-b2 70.Kc7-b6 Lb2-c1 71.Kb6-a5 Lc1-b2 72.Ka5-b4 Lb2-a1 73.Kb4-a3 Bf3-f2 74.Ka3-b4 La1-b2 75.Kb4-a5 Lb2-c1 76.Ka5-b6 Lc1-b2 77.Kb6-c7 Lb2-c1 78.Kc7-d8 Lc1-b2 79.Kd8-e7 Lb2-c1 80.Ke7-f8 Lc1-b2 81.Kf8-g7 Lb2-c1 82.Kg7-g6 Lc1-b2 83.Kg6-h6 Lb2-c1 84.Kh6-g7 Lc1-b2 85.Kg7-f8 Lb2-c1 86.Kf8-e7 Lc1-b2 87.Ke7-d8 Lb2-c1 88.Kd8-c7 Lc1-b2 89.Kc7-b6 Lb2-c1 90.Kb6-a5 Lc1-b2 91.Ka5-b4 Lb2-a1 92.Kb4-a3 Bf5-f4 93.Ka3-b4 La1-b2 94.Kb4-a5 Lb2-c1 95.Ka5-b6 Lc1-b2 96.Kb6-c7 Lb2-c1 97.Kc7-d8 Lc1-b2 98.Kd8-e7 Lb2-c1 99.Ke7-f8 Lc1-b2 100.Kf8-g7 Lb2-c1 101.Kg7-g6 Lc1-b2 102.Kg6-h6 Lb2-c1 103.Kh6-g7 Lc1-b2 104.Kg7-f8 Lb2-c1 105.Kf8-e7 Lc1-b2 106.Ke7-d8 Lb2-c1 107.Kd8-c7 Lc1-b2 108.Kc7-b6 Lb2-c1 109.Kb6-a5 Lc1-b2 110.Ka5-b4 Lb2-a1 111.Kb4-a3 Bf4-f3 112.Ka3-b4 La1-b2 113.Kb4-a5 Lb2-c1 114.Ka5-b6 Lc1-b2 115.Kb6-c7 Lb2-c1 116.Kc7-d8 Lc1-b2 117.Kd8-e7 Lb2-c1 118.Ke7-f8 Lc1-b2 119.Kf8-g7 Lb2-c1 120.Kg7-g6 Lc1-b2 121.Kg6-h6 Lb2-c1 122.Kh6-g7 Lc1-b2 123.Kg7-f8 Lb2-c1 124.Kf8-e7 Lc1-b2 125.Ke7-d8 Lb2-c1 126.Kd8-c7 Lc1-b2 127.Kc7-b6 Lb2-c1 128.Kb6-a5 Lc1-b2 129.Ka5-b4 Lb2-a1 130.Kb4-a3 Bh5-h4 131.Ka3-b4 La1-b2 132.Kb4-a5 Lb2-c1 133.Ka5-b6 Lc1-b2 134.Kb6-c7 Lb2-c1 135.Kc7-d8 Lc1-b2 136.Kd8-e7 Lb2-c1 137.Ke7-f8 Lc1-b2 138.Kf8-g7 Lb2-c1 139.Kg7-g6 Lc1-b2 140.Kg6-h6 Lb2-c1 141.Kh6-g7 Lc1-b2 142.Kg7-f8 Lb2-c1 143.Kf8-e7 Lc1-b2 144.Ke7-d8 Lb2-c1 145.Kd8-c7 Lc1-b2 146.Kc7-b6 Lb2-c1 147.Kb6-a5 Lc1-b2 148.Ka5-b4 Lb2-a1 149.Kb4-a3 Bh4-h3 150.Ka3-b4 La1-b2 151.Kb4-a5 Lb2-c1 152.Ka5-b6 Lc1-b2 153.Kb6-c7 Lb2-c1 154.Kc7-d8 Lc1-b2 155.Kd8-e7 Lb2-c1 156.Ke7-f8 Lc1-b2 157.Kf8-g7 Lb2-c1 158.Kg7-g6 Lc1-b2 159.Kg6-h6 Lb2-c1 160.Kh6-g7 Lc1-b2 161.Kg7-f8 Lb2-c1 162.Kf8-e7 Lc1-b2 163.Ke7-d8 Lb2-c1 164.Kd8-c7 Lc1-b2 165.Kc7-b6 Lb2-c1 166.Kb6-a5 Lc1-b2 167.Ka5-b4 Lb2-a1 168.Kb4-a3 Bh3-h2 169.Ka3-b4 La1-b2 170.Kb4-a5 Lb2-c1 171.Ka5-b6 Lc1-b2 172.Kb6-c7 Lb2-c1 173.Kc7-d8 Lc1-b2 174.Kd8-e7 Lb2-c1 175.Ke7-f8 Lc1-b2 176.Kf8-g7 Lb2-c1 177.Kg7-g6 Lc1-b2 178.Kg6-h6 Lb2-c1 179.Kh6-g7 Lc1-b2 180.Kg7-f8 Lb2-c1 181.Kf8-e7 Lc1-b2 182.Ke7-d8 Lb2-c1 183.Kd8-c7 Lc1-b2 184.Kc7-b6 Lb2-c1 185.Kb6-a5 Lc1-b2 186.Ka5-b4 Lb2-a1 187.Kb4-a3 Be6-e5 188.Ka3-b4 La1-b2 189.Kb4-a5 Lb2-c1 190.Ka5-b6 Lc1-b2 191.Kb6-c7 Lb2-c1 192.Kc7-d8 Lc1-b2 193.Kd8-e7 Lb2-c1 194.Ke7-f8 Lc1-b2 195.Kf8-g7 Lb2-c1 196.Kg7-g6 Lc1-b2 197.Kg6-h6 Lb2-c1 198.Kh6-g7 Lc1-b2 199.Kg7-f8 Lb2-c1 200.Kf8-e7 Lc1-b2 201.Ke7-d8 Lb2-c1 202.Kd8-c7 Lc1-b2 203.Kc7-b6 Lb2-c1 204.Kb6-a5 Lc1-b2 205.Ka5-b4 Lb2-a1 206.Kb4-a3 Ta8xa7 207.Lb8xa7 La1-b2 208.Ka3xb2  nebst 209.Tb3xc3 Se4xc3 210.Sh1xf2# 

New Gustav- update probably will be released soon, regards

[Hobacle]

Try to solve this puzzle[/size]

K7/p3p1p1/1p2p1p1/rp4B1/brpn4/Rnk5/8/4N1N1 w

Actually Gustav CAN solve this mate, see here:

https://www.chessprogramming.org/Gustav#Longest_Problem

The longest for Gustav solvable problem so far has 163 moves, not in 163 moves, I believe that the shortest amount that this puzzle can be solved is 167 moves, which is correct

Well it DOES look like Gustav can solve this in 163 moves which means it found a shorter mate as Peter has pointed out

The specific cook has been posted on P1410779.

[acase]

Try to solve this puzzle[/size]

K7/p3p1p1/1p2p1p1/rp4B1/brpn4/Rnk5/8/4N1N1 w

Actually Gustav CAN solve this mate, see here:

https://www.chessprogramming.org/Gustav#Longest_Problem

The longest for Gustav solvable problem so far has 163 moves, not in 163 moves, I believe that the shortest amount that this puzzle can be solved is 167 moves, which is correct

Well it DOES look like Gustav can solve this in 163 moves which means it found a shorter mate as Peter has pointed out

The specific cook has been posted on P1410779.

Thank you Hobacle, but I think Peter already posted that link earlier in this thread, also thanks for your interesting variations on the original mates by Fabel and all of your other interesting puzzles.