Author: Christophe Theron
Date: 11:22:38 10/20/00
Go up one level in this thread
On October 20, 2000 at 02:21:10, Uri Blass wrote:
>On October 19, 2000 at 22:23:39, Christophe Theron wrote:
>
>>On October 19, 2000 at 16:31:38, Howard Exner wrote:
>>
>>>On October 18, 2000 at 14:14:20, Uri Blass wrote:
>>>
>>>>On October 18, 2000 at 12:34:42, Ricardo Gibert wrote:
>>>>
>>>><snipped>
>>>>>The algorithm to determine whether this type of position is drawn is quite
>>>>>simple. With the h-pawn, Black draws if the K can get into the four corner
>>>>>squares g7,g8,h7,h8. Otherwise, the outcome is not assured. Note, it is not
>>>>>enough for the King to get in front of the pawn as the following position
>>>>>illustrates:
>>>>
>>>>I can give another rule:
>>>>Blacks draw if it is black to move and the distance between the black king and
>>>>the corner in king moves is smaller than the ditance between the corner and the
>>>>white pieces except the bishop(white king in king moves and white pawn in pawn
>>>>moves)
>>>>
>>>>If it is white to move then use distance-1 instead of distance for white.
>>>
>>>This is very useful, I have many endgame books and I've never seen this
>>>description. It's one thing to point out where a program goes wrong and quite
>>>another to offer a solution in programmable language, like you have done.
>>>
>>>I think we all would like to see programs have a good routine to solve this
>>>scenario.
>>
>>
>>
>>You can count on me. I'll integrate this rule in Chess Tiger and Gambit Tiger as
>>soon as it is confirmed that I can use it even when white has several pawns on
>>the A or H file.
>>
>>
>>
>> Christophe
>
>It is simple to confirm it because of the following facts.
>
>1)If the black king is in one of h8,g8,h7,g7 nothing can stop it from a draw and
>the number of pawns of white is not important.
>2)If the black king is not in h8 then the black king always control black
>squares that are closer to the corner.
>
>3)Assume it is black to move and black king is not in the corner
>My rule says that the black king is closer to the corner than the white king and
>the white pawns(the distance of pawns is in pawn moves so a pawn in h2 is the
>same as a pawn in h3 for calculating the distance).
>
>fact 2 means that black can control squares that are closer to the corner and
>that white cannot see(the bishop cannot see them because they are not in the
>right colour and the other pieces cannot see them because the distance in king
>moves is at least 2 and if the pawn is at h2 the distance in king moves is even
>3 and the pawn cannot close the gap).
>
>4)Assume that it is white to move.
>White cannot get closer to the corner with the king and the pawns by more than
>one step and my rule says that the difference in the distance is at least 2 so
>after white moves the black is still closer to the corner by at least one step
>and can continue the trip to the corner.
>
>Uri
Sounds good. I'll add the rule into Chess Tiger and Gambit Tiger.
You don't own Copyright on this rule, do you? :)
If you do I hope you will allow me to use it.
Christophe
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