Author: Dave Gomboc
Date: 16:34:17 05/23/99
Go up one level in this thread
On May 23, 1999 at 18:41:59, Mark Young wrote:
>After looking over the Rebel 10.5 - GM Rohde game with many programs, I finally
>got around to why Hiarcs 7 wants to play 23. Rxb4 instead of the move 23. exd4
>as was played in the game and most other program agree with, giving it a equal
>score or slightly minus score, but all the other programs think 24.Rxb4 is a
>mistake. (Hiarcs7 give 23. Rxb4 a +138, or better then a pawn advantage at +128)
>
>In a effort to see why Hiarcs7 is making this blunder, I played the other
>programs against Hiarcs7 after the move 23. Rxb4. To my surprise all of them
>have lost even though they think 23. Rxb4 is far from the best move and prefer
>23. exd4.
>
>If 23. Rxb4 is losing what is the winning line against this move 23. Rxb4 that
>none of the program I have tried can find.
>
>
>Here is an example of what I am seeing against other programs. Played at 40
>moves in 2 hours. This was Fritz try to bust Hiarcs 7 23. Rxb4.
>
>
>[Event ""]
>[Site ""]
>[Date "1999.04.23"]
>[Round ""]
>[White "HIARCS 7"]
>[Black "Fritz 5"]
>[Result "*"]
>[FEN "1r1qr2k/1p4pp/3p4/1R1B1p2/1pPp4/4P1Pb/1P3P1P/Q3R1K1 w - -"]
>
>{H701: 65472Kb, <3000589b>}
>23. Rxb4 {H7: 10 23.Rxb4 h6 = 138}
>23... dxe3 24. Rxe3 {H7: 11 24.Rxe3 Rxe3 fxe3 b6 Qa7 Bg4 Rb5 Qe8 Kg2 Bh3+
>Kf2 Qd8 = 140}
>24... Rxe3 25. fxe3 {H7: 11 25.fxe3 b6 = 140}
>25... Qe8 26. Kf2 {H7: 11 26.Kf2 b6 Qa7 Qd8 Be6 Bg4 = 172}
>26... Qc8 27. Rb6 {H7: 10 27.Rb6 Ra8 Qd1 Rb8 Qb3 Qf8 Rxb7 Rd8 Rf7 Qe8 Qb7
>Qe5 = 280}
>27... Qd8 28. Rxb7 {H7: 11 28.Rxb7 Rxb7 Bxb7 Kg8 Qa8 Qxa8 Bxa8 Kf7 b4 Ke7 b5
>Kd8 b6 Kc8 Bd5 = 325}
>28... Rxb7 29. Bxb7 {H7: 12 29.Bxb7 Kg8 Qa8 Qxa8 Bxa8 Kf7 b4 Ke7 Bg2 Bg4 b5
>Kd8 b6 Kc8 e4 Kb8 exf5 Bxf5 = 344} and white gos on to win.
Crafty gives Rxb4 a plus score... but at least on early iterations, a slightly
less plus score that exd4. After a continuation like
23. Rxb4 h6 24. b3 dxe3 25. Rxe3 Rxe3 26. fxe3 Bg4 27. Kg2 Kh7 White looks
pretty good. Of course, just about all of those moves might be suboptimal. :-)
Dave
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