Author: Uri Blass
Date: 05:30:04 01/03/03
Go up one level in this thread
On January 03, 2003 at 07:37:12, Drexel,Michael wrote: >On January 03, 2003 at 01:12:42, Uri Blass wrote: > >>On January 02, 2003 at 18:36:35, Drexel,Michael wrote: >> >>>On January 02, 2003 at 17:52:50, Uri Blass wrote: >>> >>>>On January 02, 2003 at 16:39:27, Drexel,Michael wrote: >>>> >>>>>On January 02, 2003 at 16:16:05, Dieter Buerssner wrote: >>>>> >>>>>>On January 02, 2003 at 15:53:44, Drexel,Michael wrote: >>>>>> >>>>>>>Hello Dieter, >>>>>>[...] >>>>>>>at which depth do you think it would find the mate? 30/30? >>>>>> >>>>>>Sorry, I am the wrong person to answer this question. How should I know? >>>>>> >>>>>>>this 'behaviour' has obviously something to do with its superior playing >>>>>>>strength. >>>>>> >>>>>>? >>>>>> >>>>>>Regards, >>>>>>Dieter >>>>> >>>>>just wanted to say that this kind of tests (with unreal or unlikely situations) >>>>>are not important, regarding playing strength. >>>>> >>>>>Michael >>>> >>>>I disagree. >>>> >>>>I believe that knowing to solve the position is an advantage from playing >>>>strength point of view. >>>> >>>>It may be unimportant if white had another win but it is not the case here. >>>> >>> >>>In this special case it is an advantage but how often would such a type of >>>position occur in the middle game? Shredder 7 and Fritz 8 (Junior and Chesstiger >>>15 results would be of interest too) are not >>>able to find the best move in reasonable time. >>>Im not a chessprogrammer but it seems clear to me that 'comercials' are able >>>to get deeper into the search, by excluding more variations then most freeware >>>programs do. hence they often fail to find mates in such positions. >> >>I reject this explanation. >>Most freeware also do not find it. > >I should have said most of the 'strongest' freeware programs. > >> >>I also use pruning but for me pruning is not the main problem because even if >>you give movei the position after Qxg6+ Kxg6 movei cannot find that white is >>better in a reasonable time. >> >>pruning is important but good pruning rules should say not prune Qxg6 in that >>position. >> >>I can give logical reasons. >>1)white has inferior position without Qxg6+. >>2)Qxg6+ lead to some attack for white. >> >>conclusion >>Qxg6+ should be extended becuse it is the only chance. > >Stefan Mayer-Kahlens program (engine) do not extend Qxg6+ as far as I can >understand. >would Shredder 7 otherwise evaluate 1.Qxg6+ only 2 seconds (1.h5 about 10 >minutes) at depth 17? >I simply cant understand why. Doesnt Stefan know what he is doing?. >I dont think so. >If I would write a chessprogram, the first thing I would probably do (after the >basics) is: >try to make some extensions in case 'King is marching over the board in a middle >game situation'. my program would evaluate 1.Qxg6+ very very long in this >position. > >so my conclusion is: with a good opening book in mind (and shredder has good >tournament book)it is not that important to have such extensions. I agree that it is not very important to have extensions when the king runs to the middle of the board but I still think that it is possible to earn some rating points from it. I do not think that it is something that has to be with opening books. I believe that in most cases the search depth is simply big enough to see cases when a sacrifice leads to win. In most cases it is better to prune moves that lose a lot of material but this position is an exception(one of the reasons is the fact that white has bad position without Qxg6+ so it is better to extend the move that seems to be a hope to save the game). Yace find it thanks to extensions that are not check extensions and I do not have the relevant extensions. I believe that I may earn also from other extensions and I am going to implement them in the next version. Uri
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.