Author: Robert Hyatt
Date: 13:57:34 06/08/01
Go up one level in this thread
On June 08, 2001 at 16:37:57, Daniel Clausen wrote: >Hi > >On June 08, 2001 at 16:23:39, Robert Hyatt wrote: > >>On June 08, 2001 at 16:21:01, Robert Hyatt wrote: >> >>>On June 08, 2001 at 16:08:52, John Merlino wrote: >>> >>>>On June 08, 2001 at 15:19:09, Robert Hyatt wrote: >>>> >>>>>Here is a cute position that occurred between a commercial program and Crafty >>>>>last week: >>>>> >>>>>[D] 8/p4pp1/3rk2p/4p3/2P5/2K4P/P2R1PP1/8 w - - 0 1 >>>>> >>>>>Crafty was black and moved the rook to d6, offering a trade. The opponent >>>>>took it and was happy to do so. Unfortunately, white is lost. White saw >>>>>the passed pawn and apparently was quite happy. Crafty's static evaluation >>>>>for this position is -1.0 roughly. >>>>> >>>>>For those that "don't do endgames" black's king-side majority is the problem >>>>>here. White's passer gets blockaded, white has to desert it to stop black's >>>>>kingside passer he makes after a few pawn moves, and then black eats white's >>>>>a pawn and promotes. >>>>> >>>>>Instructional, at least. These are the kinds of positions you want to >>>>>see your program get right. I saw a very similar one against a GM today, >>>>>playing Crafty. He calculated for a long time after crafty offered to trade >>>>>the last piece on the board. He traded, and 10 moves later realized he was >>>>>dead lost. :) >>>> >>>>How did this game end after the rooks were traded? >>>> >>>>jm >>> >>> >>>Black wins easily. >> >> >>I should have added, the point here is that white ends up in a king and pawn >>ending with a passed pawn to none for black. Black has a kingside majority that >>many programs ignore. Here it is decisive. > >I'm not a good chess player but trying to summarize. Please correct me if I'm >wrong. Black can easily transform the pawn majority on the kingside into a >passer. After that White and Black both have a passer but Black wins because his >(or her, or its :) passer is farer (is that an English word?) away than white's. >Basically a program (or a human) has to recognize that in this situation the >pawn majority for black on the kingside is worth a passer. > >Does this sound about right? > >Regards, > >Sargon Effectively, that is close. Both have an "inside passer" but white's gets stopped(blockaded) first. When white moves to do something about black's new passer on the kingside, the white pawn is lost and black gets to the queenside before white can eat enough on the kingside... I think these kinds of positions are critical to get right. years ago I only handled pawn races well. Then I added outside passed pawn code and had a good time with other programs until they started doing it also. This is just another level of "outside passer" (outside candidate) that needs handling. In addition to all the special cases like two isolated passers are better than two connected passers in a king-only ending...
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