Author: Christophe Theron
Date: 13:44:51 02/17/02
Go up one level in this thread
On February 17, 2002 at 13:48:17, Uri Blass wrote:
>On February 17, 2002 at 13:10:50, Christophe Theron wrote:
>
>>On February 17, 2002 at 12:03:18, Uri Blass wrote:
>>
>>>On February 17, 2002 at 11:43:09, Christophe Theron wrote:
>>>
>>>>On February 17, 2002 at 11:34:40, Christophe Theron wrote:
>>>>
>>>>>On February 17, 2002 at 05:43:22, Uri Blass wrote:
>>>>>
>>>>>>On February 17, 2002 at 05:21:47, Ed Schröder wrote:
>>>>>>
>>>>>>>On February 17, 2002 at 04:55:13, Steffen Jakob wrote:
>>>>>>>
>>>>>>>>Here is another position which is easy to solve for humans. In a blitz game
>>>>>>>>between Hossa and Arasan the following position was on the board:
>>>>>>>>
>>>>>>>>[D]8/8/4B2p/2K5/r5P1/p5k1/Rb6/8 b - - 7 116
>>>>>>>>
>>>>>>>>For humans it's rather easy to see that 117... Rxg4 wins without any problems
>>>>>>>>because the white rook is totally paralyzed. Unfortunately Hossa wasn't able to
>>>>>>>>see this in the blitz game. So the game continued until the 50 moves rule forced
>>>>>>>>Hossa to take the bishop and finally to win the game.
>>>>>>>>Which engines find 117... Rxg4 in which time?
>>>>>>>
>>>>>>>Easy for comps too :)
>>>>>>>
>>>>>>>2 secs for RC4
>>>>>>>
>>>>>>>Ed
>>>>>>>
>>>>>>>==============================================================
>>>>>>>
>>>>>>>00:00:02.1 1,88 9 449751 Re4 Kd6 Re3 Bf5 Kf4 Be6 Re5 Bd7
>>>>>>>00:00:02.1 1,88 9 817955 Rxg4
>>>>>>>00:00:02.1 2,09 9 835992 Rxg4 Bxg4 Kxg4 Kd5 h5 Kd6 h4 Kd5
>>>>>>>00:00:03.3 2,17 10 1122788 Rxg4 Bxg4 Kxg4 Kd5 h5 Ke4 h4 Ke3
>>>>>>>00:00:04.5 2,01 11 2027319 Rxg4 Bxg4 Kxg4 Kc4 h5 Kd3 Kf3 Kc4
>>>>>>>00:00:34.6 3,62 12 31107270 Rxg4 Bd7 h5 Bc6 Rf4 Kb5 h4 Ka5
>>>>>>>00:00:44.1 3,82 13 41624594 Rxg4 Bd7 h5 Bc6 Rf4 Bb5
>>>>>>
>>>>>>
>>>>>>Trivial for Deep Fritz
>>>>>>
>>>>>>It knows that opposite color bishops with one pawn advantage gives good chances
>>>>>>for a draw so it's only choice is to sacrifice the rook by evaluation.
>>>>>
>>>>>
>>>>>Where do you see an opposite bishops ending after Rxg4 Bxg4 Kxg4 ?
>>>>>
>>>>>
>>>>>
>>>>> Christophe
>>>>
>>>>
>>>>
>>>>Oops... Sorry.
>>>>
>>>>OK, I've got it now. It's opposite colored bishops BEFORE the above capture
>>>>sequence.
>>>>
>>>>I did not get it at first because Tiger does not consider opposite bishop
>>>>endings as drawish when there are other pieces on the board (like rooks).
>>>>
>>>>Looks like I really should have a second look at this rule... :)
>>>>
>>>>
>>>>
>>>> Christophe
>>>
>>>with rooks on the board there are better chances for a win for the stronger side
>>>but I believe that the chances for a draw are still better than the chances for
>>
>>I guess you mean "win" here ----------^^^^ ?
>
>No
>
>Maybe I did not exaplin myself clearly when I jumped from win to draw but
>I meant to what I said.
>
>Here are examples that demonstrate what I meant
>
>from the point view of the stronger side:
>
>The first diagram is better than the second diagram and the second diagram is
>better than last diagram.
>
>[D]r4b1k/ppp3pp/8/8/8/8/PPP2PPP/R1B4K w - -
>
>[D]r4b1k/ppp3pp/8/8/8/8/PPP2PPP/R4B1K w - -
>
>[D]5b1k/ppp3pp/8/8/8/8/PPP2PPP/5B1K w - -
>
>>
>>
>>>a draw in case that there are no opposite bishops.
>>
>>
>>Do you think the above still applies if you replace the rooks by queens?
>
>I am not sure about it.
>rooks with opposite bishops are more common than queens with opposite bishops.
>
>Uri
OK. Thanks for your comments, I'm going to improve Chess Tiger's knowledge of
these cases.
I'll left the queen case out of this.
Christophe
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