Author: Robert Hyatt
Date: 15:39:17 10/03/99
Go up one level in this thread
On October 03, 1999 at 13:31:53, Ed Schröder wrote: >On October 03, 1999 at 09:32:47, Robert Hyatt wrote: > >>On October 03, 1999 at 04:42:40, Ed Schröder wrote: >> >>>>Posted by Lawrence S. Tamarkin on October 03, 1999 at 02:48:13: >>>> >>>>Congratulations to Rebel Century on its win against GM Scherbakov. We here at >>>>the Marshall Chess Club Salute you! (I may just set up some match in the club, >>>>involving an IM or GM, just for fun, but especially if Rebel company (Ed), >>>>wants to draw a player from the NY chess mecca... >>> >>>You know I am always in for a challenge. And the Marshall Chess Club is >>>quite a name to remember. >>> >>>>This makes me more excited about getting Rebel Century & studying with it (I >>>>have long ago stopped playing with these programs), various positions out of >>>>chess books, and my tournament games. Bigger book, custem levels, more >>>>training features, test positons, utilities, etc, etc. It is definately a fantastic >>>>bargain, that we (I), look forward too. >>> >>>Don't tell me about it. The data on the cd is 620 Mb. It was quite difficult to >>>decide what should be left out as the limit is 640 Mb. How can one handle that >>>in one year? I wonder. Seems to me DVD has the future and will be required >>>within 2-3 years. >>> >>>>I hope Rebel Century will keep winning (No GM has yet lost in 30 moves or less >>>>to it:)), and that the GM's pride will keep them coming back for more, rather >>>>than fear scaring them away! >>> >>>We shortly discussed the possibility of a re-match. In principal we agreed to >>>that but of course we have to figure out the details in email first. >>> >>>About the game: I am pretty impressed by the attacking style. It sacrifices >>>a piece for a promising king attack. Then later counting the pieces on the >>>board Rebel is behind a full rook. Still it shows +3.xx, a dream game. >>> >>>Ed >> >> >>Rebel played well, obviously. However this is _not_ a sac. A sac is where you >>give up material for positional gain. This is a pure tactical combination as >>it wins more material than it gives up... > >What you describe is called a "positional sacrifice". I haven't used that >word. It could have been an issue too as the evaluation for king safety >in cases like yesterdays game is varying from 2-3 pawns and maybe more. > >Ed > Most books on tactics define 'sacrifice' as giving up material for some sort of compensation (either positional or long term tactical chances). They define 'combination' as a sequence of captures resulting in a gain of material. in this game, my material score is always > 0 in the position you give, meaning that Crafty sees more material coming back to it than it gives up with the original rook capture. That seems to better fit a 'combination'. I will agree that several books talk about 'queen sacrifices' when they are not really sacrifices... as giving up a queen to win the opponent's king gets more material back than it gives up... But I like the term 'combination' here... and usually use the term sacrifice as in 'sacrificing the exchange'... after the rxc3 bxc3 type sac in many Sicilian variations, black is 2 pawns (the exchange) down, yet gets lots of compensation for that material, hopefully... Or in sacrificing a pawn (such as playing a4-a3 to force your opponent to play bxa3 and end up with three isolated pawns that you hope you can eventually win, and which you _know_ can not be used to create a passed pawn... Mainly semantics... But if we call this a sacrifice, then I see one of these every 2 games or so... IE QxR RxQ BxR, because after QxR RxQ I am definitely down 4 pawns, but after the third move I am up a pawn... Bob > >>>>Larry - the chess software addict!
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