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Subject: Re: Easy for humans

Author: Uri Blass

Date: 21:56:42 02/17/02

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On February 18, 2002 at 00:33:56, Miguel A. Ballicora 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
>>a draw in case that there are no opposite bishops.
>>
>>Note that even with only bishops on the board it is not always a draw and I won
>>my last game in the israeli league thanks for the fact that I did not accept a
>>draw offer when the material was equal
>>
>>Here is the relevant position
>>
>>[D]6k1/6pp/p1b5/5p2/5P2/3p2P1/PP5P/4B1K1 w - - 0 31
>>
>>the last move of my opponent was Bb5-c6 and he offered me a draw
>>
>>I said no after some minutes of thinking because I found chances for a win
>>and the game continued Kf2 Kf7 Ke3 Be4 Kd4 and only at this point my opponent
>>understood that he has some trouble and started to think more than few seconds
>>for a move.
>
>This position looks pretty drawish. I think that Be4 is a waste of time.
>The right plan is to get the king to the center and be prepared to blockade a
>possible passed pawn (Q side) and defend the K side with the bishop.
>
>Regards,
>Miguel

I agree that Be4 is a waste of time but the last move of black
Bb5-c6 told me that the opponent plans Be4

It seems that the opponent told me in this move:
"You are not going to capture d3 so it is a waste of time from you to continue"

I was also afraid from the pawn d3 and I did not think that I have chances to
win in the first seconds.

Fortunately I do not have to answer yes or no to the draw offer in one second
and I had time to change my opinion.

Uri



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