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Subject: Re: King, rook pawn and wrong bishop endgames

Author: Oliver Roese

Date: 23:26:47 10/18/00

Go up one level in this thread


On October 19, 2000 at 01:06:03, Uri Blass wrote:

>On October 19, 2000 at 00:51:19, Christophe Theron wrote:
>
>>On October 18, 2000 at 16:31:54, Ricardo Gibert wrote:
>>
>>>On October 18, 2000 at 15:57:10, Uri Blass wrote:
>>>
>>>>On October 18, 2000 at 15:52:09, Ricardo Gibert 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.
>>>>>>
>>>>>>Uri
>>>>>
>>>>>I like your rule. It's interesting, but it needs to be amended somewhat:
>>>>>
>>>>>[D]4B3/8/8/8/8/2k5/7P/K7 b - - 0 0
>>>>
>>>>This position is not a draw by my rule.
>>>>The distance of the white pawn to the corner in pawn moves is equal(and not
>>>>smaller) to the distance of the black king to the corner in king moves.
>>>
>>>Yep, I goofed.
>>>
>>>>
>>>>>
>>>>>as you can see, your rule is a little dangerous. There may be other examples,
>>>>>but this is what I came up with in a about a minute. Still your rule is
>>>>>promising.
>>>>>
>>>>>There are some positions your rule does not give as drawn, but "my" rule does.
>>>>>The reverse is also true of course, so maybe the rules should be combined?
>>>>
>>>>I agree that the rules can be combined.
>>>>
>>>>Uri
>>
>>
>>
>>This discussion is very interesting. So what's the ultimate rule?
>>
>>I had to work on this recently in Chess Tiger (and Gambit Tiger of course), and
>>I'm not sure my own rule is as good as yours.
>>
>>Waiting eagerly for the next post...
>>
>>
>>
>>    Christophe
>
>The logic behind my rule is simple
>
>If black king is closer to the corner than the white king and the white pawn
>nothing can stop it if it begins a trip to the corner.
>
>It can do the trip using squares that the bishop does not control and the other
>pieces cannot see these squares.
>
>Uri

Looks good.
And is harp, since i have counterexamples if one of the constraints is relaxed
by one.

Oliver



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