Author: Peter McKenzie
Date: 10:27:28 02/17/02
Go up one level in this thread
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 ----------^^^^ ? > > >>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 would say no. The theory is that you have more chances against the King when there are bishops of opposite colours, so with queens on this is probably a factor. Hmm, maybe this could be a term for general king safety? Bump up the king safety score slightly if there are bishops of opposite colours?! > > > > Christophe
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