Author: James T. Walker
Date: 10:32:31 12/23/00
Go up one level in this thread
On December 23, 2000 at 12:43:58, Uri Blass wrote:
>On December 23, 2000 at 09:59:54, James T. Walker wrote:
>
>>On December 22, 2000 at 23:55:46, Uri Blass wrote:
>>
>>>On December 22, 2000 at 20:06:11, James T. Walker wrote:
>>>
>>>>I recently made the statement that Shredder was not a "Blitzer". I'm issuing a
>>>>recall of that statement. I just finished a 20 game match of Gambit Shredder vs
>>>>Chess Tiger 13 (G/5minutes). Gambit Shredder won +8 -6 =6 (11-9). That does
>>>>not necessarily mean Gambit Shredder is better than Chess Tiger but it does
>>>>indicate it can play with the Tiger. Below is game 17 of the match in which
>>>>Gambit Shredder announced "Mate in 67". Of course it's a tablebase win in a
>>>>very difficult KBBKN endgame.
>>>
>>>The question is if it is not a draw by the 50 move rule against the right
>>>defence.
>>>
>>>There are 2 questions:
>>>1)Can shredder win against itself(does it capture the knight early enough to
>>>avoid a draw)?
>>>
>>>2)Is there a win for white against the right defence?
>>>
>>>The 2 questions are different because the best move for the side with the
>>>bishops may be not the shortest way to force mate when you consider the 50 move
>>>rule.
>>>
>>>I guess that you can answer only 1 because I do not know of a program that use
>>>the right KBB vs KN tablebases of distance to conversion and not distance to
>>>mate.
>>>
>>>Uri
>>
>>Here is the position and the "Autoplay" of Shredder 5. So I believe this
>>answers the question. I think since Shredder captures the Knight on its 50th
>>move the game is won even under the 50 move rule which is not a mandatory rule
>>if I understand correctly. I believe if you are playing computer/computer games
>>with tablebases involved you would wave the 50 move rule. The only reason for
>>the 50 move rule in the first place is that humans could play on forever and not
>>make progress. This does not apply to computers with tablebases. I made the
>>diagram with black on the move since white has just captured the pawn. This
>>does bring up the question of when to start the count if using the 50 move rule.
>> I assume it starts on whites next move after the capture (move 2 below). The
>>Knight is captured on the 50th move if my count is correct.
>>Jim
>>
>>[D]8/6B1/8/8/1k6/8/K7/3B4 b - - Mate in 67 for white
>>
>>[Event "5 Minutes/game"]
>>[Site "?"]
>>[Date "2000.12.23"]
>>[Round "?"]
>>[White "Gambit Shredder"]
>>[Black "Chess Tiger 13"]
>>[Result "*"]
>>[SetUp "1"]
>>[FEN "8/2n4B/8/8/K2B1k2/8/8/8 b - -"]
>>
>>1... Ne6 {-M66/4 0s} 2. Bb2 {+M66/4 0s} Ng5 {-M65/4 0s}
>>3. Bc1+ {+M65/4 0s} Kg4 {-M64/4 0s} 4. Bd3 {+M64/4 0s} Ne6
>>{-M63/4 0s} 5. Kb5 {+M63/4 0s} Nf4 {-M62/4 0s} 6. Bc2
>>{+M62/4 0s} Kf3 {-M61/4 0s} 7. Kc4 {+M61/4 0s} Ne6 {-M60/4
>>0s} 8. Bb2 {+M60/4 0s} Nf4 {-M59/4 0s} 9. Kd4 {+M59/4 0s}
>>Kf2 {-M58/4 0s} 10. Ke5 {+M58/4 0s} Kf3 {-M57/4 0s}
>>11. Be4+ {+M57/4 0s} Kg3 {-M56/4 0s} 12. Kf5 {+M56/4 0s}
>>Ng2 {-M55/4 0s} 13. Be5+ {+M55/4 0s} Kf2 {-M54/4 0s}
>>14. Bc7 {+M54/4 0s} Ne1 {-M53/4 0s} 15. Bb6+ {+M53/4 0s}
>>Kg3 {-M52/4 0s} 16. Bd5 {+M52/4 0s} Ng2 {-M51/4 0s} 17. Kg5
>>{+M51/4 0s} Ne1 {-M50/4 0s} 18. Bc7+ {+M50/4 0s} Kf2
>>{-M49/4 0s} 19. Kg4 {+M49/4 0s} Ke3 {-M48/4 0s} 20. Bb6+
>>{+M48/4 0s} Kd3 {-M47/4 0s} 21. Bf7 {+M47/4 0s} Nc2 {-M46/4
>>0s} 22. Bg6+ {+M46/4 0s} Kc3 {-M45/4 0s} 23. Ba5+ {+M45/4
>>0s} Kb3 {-M44/4 0s} 24. Kf4 {+M44/4 0s} Nb4 {-M43/4 0s}
>>25. Bf7+ {+M43/4 0s} Ka4 {-M42/4 0s} 26. Bb6 {+M42/4 0s}
>>Kb5 {-M41/4 0s} 27. Be3 {+M41/4 0s} Kc6 {-M40/4 0s} 28. Ke5
>>{+M40/4 0s} Nd3+ {-M39/4 0s} 29. Kd4 {+M39/4 0s} Nc5
>>{-M38/4 0s} 30. Bd5+ {+M38/4 0s} Kb5 {-M37/4 0s} 31. Bf2
>>{+M37/4 0s} Kb4 {-M36/4 0s} 32. Bf7 {+M36/4 0s} Nb3+
>>{-M35/4 0s} 33. Ke4 {+M35/4 0s} Nc5+ {-M34/4 0s} 34. Kd5
>>{+M34/4 0s} Na4 {-M33/4 0s} 35. Kd4 {+M33/4 0s} Nc5 {-M32/4
>>0s} 36. Be1+ {+M32/4 0s} Kb5 {-M31/4 0s} 37. Kd5 {+M31/4
>>0s} Nb3 {-M30/4 0s} 38. Be8+ {+M30/4 0s} Kb6 {-M29/4 0s}
>>39. Kd6 {+M29/4 0s} Ka6 {-M28/4 0s} 40. Bd7 {+M28/4 0s} Kb6
>>{-M27/4 0s} 41. Bc3 {+M27/4 0s} Ka6 {-M26/4 0s} 42. Bg4
>>{+M26/4 0s} Kb5 {-M25/4 0s} 43. Be2+ {+M25/4 0s} Ka4
>>{-M24/4 0s} 44. Bd1 {+M24/4 0s} Ka3 {-M23/4 0s} 45. Kd5
>>{+M23/4 0s} Ka2 {-M22/4 0s} 46. Kc4 {+M22/4 0s} Nc1 {-M21/4
>>0s} 47. Bg7 {+M21/4 0s} Ka3 {-M20/4 0s} 48. Kc3 {+M20/4 0s}
>>Na2+ {-M19/4 0s} 49. Kc2 {+M19/4 0s} Ka4 {-M18/4 0s}
>
>The last move is a big mistake.
>
>Black can draw by the 50 move rule with 49...Nb4+
>
>I think that the position with all the game is a good test position for chess
>programs.
>
>The main question is if the program can find 49...Nb4+ 50.Kb1 Nd5.
>
>I am interesting if there is a program with tablebases that can find these
>moves.
>
>I suspect that a lot of programs are going to do Shredder's mistake(49...Ka4)
>and I suspect that a lot of programs are going to play 50...Nc2 that is the only
>losing move by the rules of chess after 49...Nb4+ 50.Kb1(the 50 move rule is one
>of the rules).
>
>Uri
Hello Uri,
You make a good point. But I still believe the 50 move rule can be waived
before the start of any tournament.
Anyway the "autoplay" function of Shredder is probably not a good way to test
the position because I'm sure since it's switching sides each move it is losing
the 50 move count. So if it were an actual game it would not play the Ka4 move
but play a move to claim the 50 move draw. This brings up another question.
Would Shredder play the exact same line if playing another opponent and saw the
50 move rule coming? As you know sometimes there are several moves available
that lead to mate in the same number of moves. Maybe in a real game Shredder
would be forced to take one which avoids the 50 move rule and wins after all. I
will have to see if I can make this happen against Fritz or some other program.
Jim
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