Author: Uri Blass
Date: 12:57:03 12/13/02
Go up one level in this thread
On December 13, 2002 at 14:57:12, Omid David Tabibi wrote: >On December 13, 2002 at 14:32:09, John Merlino wrote: > >>On December 13, 2002 at 14:10:02, Omid David Tabibi wrote: >> >>>On December 13, 2002 at 12:25:55, John Merlino wrote: >>> >>>>On December 13, 2002 at 11:11:07, Omid David Tabibi wrote: >>>> >>>>>On December 13, 2002 at 10:44:47, Vincent Diepeveen wrote: >>>>> >>>>>>On December 12, 2002 at 15:56:43, Omid David Tabibi wrote: >>>>>> >>>>>>[snip] >>>>>>>Finding 13.Bb5 should be very easy for every computer. This opening was first >>>>>>>introduced in a match between national teams of USSR and Argentina. The >>>>>>>Argentinians played this opening on several boards (not expecting 13.Bb5), all >>>>>>>the Russian Grandmasters found 13.Bb5 and went on to crush black. >>>>>> >>>>>>where is the output of genesis? >>>>> >>>>>White(13): f1b5 >>>>>[book] >>>>> >>>>>;-) >>>>> >>>>>>Vincent >>>> >>>>This is the same with CM9000, and 13...Rh7 is also in the book (but no further >>>>moves). So, in a sense, the engine doesn't even NEED to find that move. I was >>>>using the analysis feature in my previous posts about this position, and this >>>>feature does not access the opening book. >>>> >>>>FYI, the CM8000 book plays 8...Qc7 in this line, and does not have any response >>>>to 8...h6. >>>> >>>>So maybe I DID make (or, rather, GENERATE) some improvements to the CM9000 book, >>>>eh? >>>> >>> >>>Now the CM's opening book consists of more data, but is this extra data useful >>>(if not dangerous)? It depends. Is CM aware of the drawish nature of the >>>Gothenburg variation? For example, if CM is playing for a win, will it "know" to >>>avoid the Gothenburg variation and instead head for the classical 8...Qc7 ? >>> >>>P.S. If black is playing for a win, he'd better avoid playing 7...Be7 in this >>>variation, and instead, play 7...Qb6 heading towards the poisoned pawn >>>variation. >> >>Here is what is in the CM9000 default opening book at the moves you have >>mentioned: >> >>After 7.f4 >>-- 7...Qb6, 1/4 probability >>-- 7...Be7, 1/4 >>-- 7...Nbd7, 1/6 >>-- 7...Qc7, 1/6 >>-- 7...b5, 1/6 >>Also, the moves 7...Bd7, 7...Nc6 and 7...h6 are in the book but have zero >>probability. >> >>After 8.Qf3 >>-- 8...Qc7, 3/4 probability >>-- 8...h6, 1/4 probability >>Also, the move 8...Nbd7 is in the book but has zero probability. > >In addition to the probability, a gross evaluation is also essential for optimal >tournament play. For example, if it is playing for a win, it should eliminate >all drawish lines (i.e., set their probability to 0) from the list of choices. > >BTW, under perfect play by both sides, 13.Bb5 leads into a draw, that is why >13.Bc4 has become more popular in the last years. and how can an engine know it without someone who write a big opening book manually. Using statistics seems to me a bad idea because it is possible that only in the last game players found an idea to win so the fact that the statistics say that it was draw in most of the games may be misleading. I think that if the engine is better then the opponent and the author is afraid from opening preperation then, the best way to try to play for a win with white in a tournament may be simply to play lines that are not bad but also not popular so it is possible to throw the opponent out of book in equal position after a few moves. you can start 1.c3 or 1.d4 d5 2.Bd2 There are a lot of options to start and to get equal position and most of the chances that the opponent has not a special preperation against the option that you choose. Uri
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