Author: Uri Blass
Date: 10:53:43 02/17/02
Go up one level in this thread
On February 17, 2002 at 13:27:28, Peter McKenzie 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 ----------^^^^ ? >> >> >>>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. The question is what happens when there is only queen and no other pieces I also know that when there are a lot of pieces on the board opposite bishops help the attacker. I also remember now that kasparov beated deeper blue in game 2 of the first match in an endgame with only queens and opposite bishops but I suspect that deeper blue did not find the right defence. Maybe we may analyze it today to find the positions when deeper blue blundered. Deeper blue lost 2 pawns in that endgame so kasparov could later trade queens and win the game. Uri
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