Author: Omid David Tabibi
Date: 09:00:59 01/01/03
Go up one level in this thread
On January 01, 2003 at 11:46:56, Drexel,Michael wrote: >On January 01, 2003 at 11:17:21, Omid David Tabibi wrote: > >>On January 01, 2003 at 09:36:02, Drexel,Michael wrote: >> >>>On January 01, 2003 at 08:48:39, Omid David Tabibi wrote: >>> >>>>[D] r1bqk1nr/pppp1ppp/2n5/2b1p3/1PB1P3/5N2/P1PP1PPP/RNBQK2R b KQkq b3 0 4 >>>> >>>>The Evans Gambit, arising after 1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.b4, is a good >>>>example of positional material sacrifice. By sacrificing his b pawn, white gains >>>>a number if precious tempos, thus seizing the opening initiative. While the 4.b4 >>>>gambit might not be better than the other 4th moves here, it usually reaches a >>>>balanced position in which white has enough compensation for the sacrificed >>>>pawn. >>> >>>usually? important are only chess games with a good defence by black. >>>this gambit is probably at least slightly better for black (according to latest >>>theory). >> >>These are the statistics at NewInChess online database >>(http://www.newinchess.com/NICBase/Default.aspx?PageID=400): >> >>1071 game(s): 517 white win(s) >> 368 black win(s) >> 186 draw(s) >>White score: 56.9% >> > >my database has roughly 2000 games and white scores 58%. >however this means nothing: > >whites average ELO: 2260 >blacks average ELO: 2253 > >4...Bxb4 : Black scores below average (41%) >4...Bxb6 : Black scores well (54%) > I often prefer the NIC database (I grew up with NIC's Yearbooks!), its results seem to be more credible. Anyway, by no means did I mean that 4.b4 is better than the classical 4.c3. But unlike other dubious old gambits, in the Evans Gambit white has a true compensation. In Nunn's Chess Openings for example, most lines are evaluated as "white is slightly better", "equal position", or "unclear position"; although there exist lines which are evaluated as "white is slightly better". So, I think a realistic evaluation would be something in the range (-0.20, +0.20). > >> >> >>>I give you some examples: >>> >>> >>>Gikas,B (2254) - Kosashvili,Y (2543) [C52] >>>Curacao 40th anniv op Curacao (3), 02.11.2002 >>> >>>1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.b4 Bxb4 [4...Bb6 5.a4 a6 6.Nc3 (6.0-0 Nf6 7.d3 d6 >>>8.c3 0-0 9.Be3 Bxe3 10.fxe3 Ne7 11.Qe1 Ng6 12.Nbd2 Qe7 13.Nh4 Be6 14.Nf5 Qd7 >>>15.g4 Bxc4 16.dxc4 Nxg4 17.Qg3 Nh6 18.h4 Kh8 19.Kh2 Rg8 20.h5 Ne7 21.Nf3 Nexf5 >>>22.Qh3 g5 23.exf5 g4 24.Qh4 Qxf5 25.e4 Qf4+ 0-1 Bueno Abalo,M-Korneev,O/Ferrol >>>2002) 6...d6 7.Nd5 Nf6 8.Nxb6 cxb6 9.d3 0-0 10.c3 d5 11.exd5 Nxd5 12.Ng5 f6 >>>13.Ne4 Kh8 14.0-0 Be6 15.Rb1 Qd7 16.Re1 Bg8 17.Bd2 Rfd8 18.Qf3 Nce7 19.Bb3 Qf5 >>>20.Qxf5 Nxf5 21.Bd1 Nd6 22.Nxd6 Rxd6 23.Bf3 Rd7 24.Bg4 Rd6 25.Bf3 Rd7 26.d4 exd4 >>>27.cxd4 Bf7 28.Bg4 Rdd8 29.Rbd1 h5 30.Be2 Rac8 31.Rc1 Kg8 32.Kf1 g6 33.g3 Kg7 >>>34.h3 Rxc1 35.Rxc1 Rd7 36.b5 a5 37.g4 hxg4 38.hxg4 Nc7 39.f3 Bb3 40.Bd1 Bxd1 >>>41.Rxd1 Kf7 42.Rc1 Nd5 43.Ke2 Rc7 44.Rxc7+ Nxc7 45.Kd3 Nd5 46.Be3 Ke6 47.Bc1 Kd6 >>>48.Bh6 ½-½ Comp Deep Shredder-Milov,V/Biel 2002] 5.c3 Ba5 [5...Bd6 6.d4 Nf6 >>>7.0-0 0-0 8.Re1 h6 9.Nbd2 Re8 10.Bd3 exd4 11.cxd4 Bf8 12.e5 Nd5 13.Bc4 Nb6 >>>14.Bb3 d6 15.Qc2 dxe5 16.Nxe5 Nxe5 17.dxe5 Be6 18.Bb2 Nd5 19.Qe4 Nb4 20.Rad1 Qc8 >>>21.a3 Bxb3 22.Nxb3 Nc6 23.f4 Qe6 24.Qc2 Qg4 25.f5 Rad8 26.Rxd8 Rxd8 27.e6 f6 >>>28.Rf1 Qa4 29.Qc3 Qb5 30.Qg3 Rd3 31.Qg6 Rxb3 32.Qf7+ Kh7 0-1 >>>Sermek,D-Mikhalchishin,A/Bled 2002; >>>5...Be7 6.Qb3 Nh6 7.d4 Na5 8.Qb5 Nxc4 9.Bxh6 gxh6 10.Qxc4 exd4 11.cxd4 c6 12.d5 >>>Bf6 13.e5 Bg7 14.d6 b5 15.Qg4 0-0 16.Nbd2 f6 17.0-0 fxe5 18.Rae1 Qf6 19.Qb4 a5 >>>20.Qc5 Qe6 21.a4 bxa4 22.Nxe5 Qd5 23.Qxd5+ cxd5 24.f4 Ra6 25.Ra1 Rxd6 26.Rxa4 >>>Ra6 27.Nb3 d6 28.Nf3 Bd7 29.Rxa5 Rxa5 30.Nxa5 Rxf4 31.Rd1 d4 32.Nb3 Ba4 33.Rd3 >>>Bb5 34.Rd2 d3 35.Nc1 Bc3 36.Rd1 d2 37.Nxd2 Bxd2 0-1 Pirrot,D-Jenni,F/Cappelle la >>>Grande 2002/CBM 87 ext (37)] 6.d4 d6 7.Qb3 Nxd4 8.Nxd4 exd4 9.Bxf7+ Kf8 10.Bxg8 >>>Rxg8 11.0-0 d3 12.Qd5 Bb6 13.e5 Qd7 14.exd6 Qf5 15.Qxf5+ Bxf5 16.dxc7 Rc8 17.Na3 >>>Rxc7 18.Nb5 Rd7 19.Ba3+ Kf7 20.Nd6+ Kg6 21.Rad1 h5 22.Rfe1 Rgd8 23.Nc4 Bc7 >>>24.Bc5 b5 25.Nd2 Ba5 26.Be7 Rc8 27.Bb4 Bxb4 28.cxb4 Rc2 29.Nf3 d2 30.Ne5+ Kh7 >>>31.Rf1 Rd5 32.f4 Rxa2 33.Kf2 Bc2 0-1 >>> >>>4...Bb6 is known to be save. black can play for a win in the complicated lines >>>after 4...Bxb4. >>> >>> >>>> >>>>Now let us see how the top engines evaluate this position. There is not much >>>>tactics involved here, so this gives us a good opportunity to compare the >>>>programs' evaluation (their chess knowledge). >>>> >>>>In the table below, the evaluation of each engine is recorded after 1 minute >>>>analysis (since the evaluation is largely positional, no significant score >>>>change was noticed from one ply to another, so most probably even deeper >>>>searches will not change the result): >>>> >>>> >>>>Engine Score >>>>------ ----- >>>>Junior 7 0.06 >>>>Fritz 7 -0.41 >>>>Shredder 6.02 -0.33 >>>>Chess Tiger 14 -0.82 (Gambit Tiger 2 also produced the same score) >>>>Hiarcs 8 -0.84 >>>>Crafty 19.1 -0.81 >>> >>> Shredder 7 -0.21 >>> >>>> >>>> >>>>Interesting points: >>>> >>>> - Junior 7 was the only program who evaluated the position realistically. >>>> >>> I think junior evaluates this position too optimistic. >>> >>> >>>> - Gambit Tiger 2 which is tuned for sacrificial play, did not evaluate >>>> the position differently from Chess Tiger 14. >>>> >>>> - Hiarcs 8 which is said to incorporate the most chess knowledge, displays >>>> the least chess understanding in this position! (Conclusion: more chess >>>> knowledge does not necessarily mean better evaluation.) >>>> >>>>Omid. >>>> >>>>P.S. An analysis of Fritz 8 and Shredder 7 will be appreciated. >>> >>> >>> btw Happy New Year
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