Author: Marc van Hal
Date: 17:35:10 12/08/02
Go up one level in this thread
On December 08, 2002 at 15:32:14, Uri Blass wrote: >On December 08, 2002 at 15:09:15, Mike S. wrote: > >>On December 08, 2002 at 08:34:16, Bob Durrett wrote: >> >>>I am interested in knowing whether or not modern chess engines recognize >>>advantages of these types. >> >>It is probably inavoidable, that the simple positions I tried to design are >>mixtures of various advantages and disadvantages. Hopefully the main element is >>the one in your question, each: >> >>>(1) If the White side has a substantial space advantage, but nothing else, will >>>the chess engine evaluate the positions with that advantage and give it a high >>>score? >> >>[D]rnbqkbnr/pppppppp/8/PPPPPPPP/8/8/8/RNBQKBNR w KQkq - 0 1 >> >>Analysis by Fritz 7: >> >>1.h6 gxh6 2.Nf3 hxg5 3.Nxg5 Nh6 4.Bd3 >> +- (1.53) Depth: 5/32 00:00:00 93kN >> ± (1.31) Depth: 6/25 00:00:00 124kN >>(...) >>1.h6 g6 2.e6 dxe6 3.Bb2 e5 4.fxg6 hxg6 5.h7 Nd7 6.c6 bxc6 7.hxg8Q >> +- (1.44) Depth: 10/39 00:00:18 5080kN >> +- (2.34) Depth: 11/43 00:00:48 14730kN >> >>Analysis by Chess Tiger 14.0: >> >>1.h6 gxh6 2.Qh5 e6 3.fxe6 dxe6 4.d6 hxg5 5.Bxg5 Qd7 6.c6 >> +- (2.18) Depth: 8 00:00:00 55kN >> +- (1.66) Depth: 9 00:00:02 308kN >>(...) >>1.h6 g6 2.fxg6 fxg6 3.e6 dxe6 4.Bb2 Nf6 5.d6 cxd6 6.cxd6 exd6 7.Bxf6 >> +- (2.62) Depth: 11 00:00:26 3734kN >> +- (3.06) Depth: 12 00:00:52 8330kN >> >>Interesting, that both start with 1.h6 and later come back to it, consindering >>some other moves in between (I snipped them to save place). The engines >>immediatly choose a move which weakens Black's king position. > >This is a bad example because simple square table programs can see white >advantage because it is better to push pawn forward. > >h6 simply wins material > >New position >rnbqkbnr/pppppppp/7P/PPPPPPP1/8/8/8/RNBQKBNR b KQkq - 0 1 > >Analysis by yace_mo: > >1...gxh6 2.gxh6 > = (0.00) Depth: 1 00:00:02 >1...gxh6 2.gxh6 > = (0.00) Depth: 2 00:00:02 >1...gxh6 2.gxh6 e6 3.dxe6 > = (0.00) Depth: 3 00:00:02 >1...gxh6 2.gxh6 e6 3.dxe6 dxe6 > = (0.00) Depth: 4 00:00:02 >1...gxh6 2.gxh6 e6 3.dxe6 dxe6 4.fxe6 > = (0.00) Depth: 5 00:00:02 5kN >1...gxh6 2.gxh6 e6 3.dxe6 dxe6 4.fxe6 fxe6 5.Qxd8+ Kxd8 > = (0.00) Depth: 6 00:00:02 26kN >1...gxh6 2.gxh6 e6 3.dxe6 dxe6 4.fxe6 fxe6 5.Qxd8+ Kxd8 6.Be3 > = (0.00) Depth: 7 00:00:02 55kN >1...gxh6 2.gxh6 e6 3.dxe6 dxe6 4.fxe6 fxe6 5.Qxd8+ Kxd8 6.Be3 Be7 > = (0.00) Depth: 8 00:00:02 273kN >1...gxh6 2.e6 dxe6 3.Bb2 e5 4.Bxe5 hxg5 5.Bxh8 Nd7 > ² (0.40) Depth: 9 00:00:04 1007kN >1...gxh6 2.e6 dxe6 3.Bb2 e5 4.Bxe5 f6 5.Qh5+ Kd7 6.c6+ bxc6 7.bxc6+ Nxc6 > ± (1.00) Depth: 9 00:00:05 1007kN >1...c6 2.dxc6 > ± (0.99) Depth: 9 00:00:12 3803kN >1...c6 2.dxc6 bxc6 3.bxc6 dxc6 4.Qxd8+ Kxd8 5.hxg7 Bxg7 6.f6 exf6 7.exf6 Bf8 >8.Be3 > = (0.00) Depth: 9 00:00:22 8503kN >1...c6 2.dxc6 bxc6 3.bxc6 dxc6 4.Qxd8+ Kxd8 5.hxg7 Bxg7 6.f6 exf6 7.exf6 Bf8 >8.Be3 Nd7 > = (0.00) Depth: 10 00:00:53 21877kN >1...c6 2.hxg7 Bxg7 3.f6 Bf8 4.g6 fxg6 5.Bd3 Qc7 6.d6 exf6 7.dxc7 cxb5 > ² (0.40) Depth: 11 00:01:31 39504kN >1...c6 2.Bb2 e6 3.hxg7 cxd5 4.gxh8Q Qxa5+ 5.Rxa5 Nf6 > ± (1.40) Depth: 11 00:02:34 67365kN >1...c6 2.Bb2 e6 3.hxg7 Bxg7 4.f6 Bf8 5.g6 fxg6 6.dxe6 Bxc5 7.f7+ Kf8 8.fxg8Q+ >Rxg8 9.bxc6 > +- (1.80) Depth: 11 00:02:43 70901kN > >(blass, tel-aviv 08.12.2002) > >>>(2) If the White side has a substantial time (or development) advantage, but >>>nothing else, will the chess engine evaluate the positions with that advantage >>>and give it a high score? >> >>This was the starting position in a large experiment, published in the CSS >>magazine 4/2002: >> >>[D]rnbqkbnr/pppppppp/8/8/3PP3/2NB1N2/PPPBQPPP/R3K2R b KQkq - 0 7 >> >>In a tournament (double round robin) Black (!) managed to achieve a 20% score. - >>So, not even such a large developement advantage is a guarantee to win in >>computer chess. > >Again bad example because it is solved by piece square table. > >Uri The disadvantage of this kind of experiments is that programs ofcourse evaluate positions with forwarded pawns as good but a) not only the mobilety but b) also the valeu of passed pawns! But you must be carefull with this. A typical eror a program could make is advancing a pawn in such a way there is no play left to open the position. And this should be considered in it's evaluation. The most important factor always is time (tempo) and you loose tempo's when a pawn can't be moved any further. A very good examle of this kind of failure can be seen in the thinking lines and evaluation when it plays a French defence without a book. Though the oldies had more problems with it then the curent programs. A good example of positions with much passed pawns are the Pirc Austrian attack And the four pawn variation of the Kings Indian the last is not favourable for White as practice has shown. Simply because the pieces have to work to hard defending the pawns. Wich also means loss of mobilety. Or it must sacrefice material to gain mobiety! Regards Marc
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