Author: Dagh Nielsen
Date: 05:15:53 03/05/06
Go up one level in this thread
On March 04, 2006 at 23:51:12, Robin Smith wrote: >In the following obscure opening Rybka comes up with a TN pawn sac that seems >highly dubious to me: 1.d4 Nf6 2 c4 e5 3 dxe5 Ng4 4 Nf3 Bc5 5 e3 Nc6 6 Be2 O-O 7 >O-O Re8 8.Qd5 > >[D] r1bqr1k1/pppp1ppp/2n5/2bQP3/2P3n1/4PN2/PP2BPPP/RNB2RK1 b - - 0 8 > >Here Rybka wants to play 8...d6?! but it doesn't seem to me that Black has >enough compensation for the pawn. > >Of perhaps more theoretical interest, after 1.d4 Nf6 2.c4 e6 3.Nf3 b6 4.g3 Ba6 > >[D] rn1qkb1r/p1pp1ppp/bp2pn2/8/2PP4/5NP1/PP2PP1P/RNBQKB1R w KQkq - 0 5 > >Rybka for a while considers 5.Nc3?! (later dropping this move to its second >choice, but still seeing a slight white advantage if you force 5.Nc3). > >How can Rybka be so successful in engine tournaments conducted with small >opening books if it is so willing to enter into dubious sacs? Or am I missing >something and these sacs are actually sound? > >-Robin Yes, it is true that Rybka does not punish pawn losses in the opening so severely. One example is 1. b4 Nf6 2. a3 e5 3. Nf3, and now Rybka includes the pawn loss 3.. d5 among its top choices, depending on ply depth. Another example is 1. c4 e5 2. Nc3 Nf6 and now Rybka also includes 3. g4?! as a viable move. After the move, at depth 12, it gives an evaluation like -0.12, while Fritz 9 gives something like -0.85. These sacs are of course not sound, but they happen rarely :-) Rybka is a mysterious engine, sometimes it finds the right principle variation in an instant while Fritz 9 struggles to find it, so that I sometimes think there is a devil inside my computer. Kind regards, Dagh Nielsen
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.