Author: blass uri
Date: 14:36:48 06/13/00
Go up one level in this thread
On June 13, 2000 at 16:40:54, blass uri wrote: >On June 13, 2000 at 15:45:28, Christophe Theron wrote: > >>On June 13, 2000 at 08:36:24, Oliver Roese wrote: >> >>>On June 12, 2000 at 05:46:59, Rémi Coulom wrote: >>> >>>>On June 10, 2000 at 13:44:35, blass uri wrote: >>>> >>>>>On June 10, 2000 at 11:54:17, Ed Schröder wrote: >>>>> >>>>[...] >>>>>> >>>>>>Maybe the opposite is true. It depends per program how the programmer >>>>>>looks at things. For this position I would say that having 2 outside >>>>>>passers usually is a great advantage and as such is rewarded by a chess >>>>>>program. If so then this position is an exception to the rule. And the >>>>>>end-game is full of exceptions much more than the mid-game. >>>>>> >>>>>>Ed >>>>> >>>>>Having 2 outsides passed pawns is an advantage but having 2 advanced passed pawn >>>>>is also an advantage. >>>>> >>>>>The problem is to know which advantage is bigger. >>>>> >>>>>I agree that it is not a simple problem and I understand the fact that >>>>>programmers prefer to waste more time about other problems. >>>>> >>>>>I still believe that it is possible to see it at evaluation time by an array >>>>>64*64*64 of distance to promotion. >>>> >>>>You are perfectly right about this idea. I do it in TCB. I have a table for >>>>distance to promotion for KPK and PPK. In fact, it is not really a table of >>>>distance to promotion, but a table that gives the maximum number of "not a King >>>>move by the opponent" before the pawn is promoted. I call it "extended square of >>>>the King". It is not in the latest version of TCB. I will make it available in >>>>the next version. If programmers are interested in the code to generate the >>>>table, I will send it to them. >>>> >>>>PPK is nice, but KPK is probably much more useful. TCB can solve WAC #100 in 25 >>>>seconds or so on a celeron 400 thanks to it. It saves 3 or 4 plies as compared >>>>to the standard "square of the Pawn" rule (or is it "square of the King"?). It >>>>is also very good at detecting that a pawn can win a tempo by checking the >>>>opponent on its way to promotion. >>>> >>>>I do not think it would solve this position though. I am not a good chess >>>>player, but the position after the Queen exchange seems unclear to me. Black can >>>>promote first, but White will promote on the next half move. Is it a winning >>>>advantage? Or I might be missing something. I will try it on TCB when I am back >>>>home. >>>> >>>>Greetings, >>>>Remi >>> >>>Here is a human-like approach: >>>Apply the rule of the "wandering square". I got it from Awerbachs book about >>>pawnendings: >>> >>>[D]8/8/1k6/8/P2P4/8/8/K7 w - - 0 1 >>> >>>In the above diagram the two white pawns are on the corners of a square >>>(a4-d4-a7-d7). The rule say, that the two pawns are unstoppable by the opposite >>>king, if their common square has reached the edge of the board. >>>Since this is not the case, here black has hope to stop the pawns. (He will hold >>>the draw with 1..Ka5). >>> >>>[D]Q3q3/4k3/8/5p2/2p5/8/P6P/4K3 w - - 0 1 >>>This position is from blass uri. >>>According to the rule the white pawns are unstoppable. >>>But the blacks pawns are unstoppable to, after the unavoidable ...f4. >>>Since we have no dumb advice here, a search is required. It reveals, that black >>>wins after 1.Qxe8+ but he is only up a tempo. >>> >>>Oliver Roese >> >> >>Your rule is interesting, but I have a hard time believing that it holds when >>the pawns are on their original square. A pawn on its original square can move >>two squares up (or down), and that should imply a special case for your rule, >>isn't it? >> >> >> >> Christophe > >The rule is not correct in another case >[D]8/8/PkP5/8/8/8/8/7K w - - 0 1 > >The rule is that white wins but it is a draw. > >Uri [D]8/8/8/8/P1k1P3/6p1/7p/7K w - - 0 1 Here is another example that I invented when the rule fails. The rule is correct here that white pawns are unstoppable but cannot see that black pawns+king also cannot be stopped. Uri
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