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Subject: Re: Kasparov vs Topalov - Flawed analysis at ChessBase website?

Author: Stan Arts

Date: 11:08:55 03/05/04

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On March 05, 2004 at 13:35:31, Roy Brunjes wrote:

>The ChessBase site reports on Linares and provides PGN files if the games.  At
>least some of these games even have analysis.  The game between Kasparov and
>Topalov was analyzed, apparently with Fritz (version unknown).  The key position
>is here:
>
>[D] 2b2rk1/2pn1p2/3p2pB/2nPp2N/4P2b/2P3RN/q1B2PP1/3Q2K1 w - - 0 27
>
>The report says that Kasparov missed a win with 27. Rxg6+!!
>
>In analyzing this game with Chessmaster 9000, it does not prefer to play 27.
>Rxg6+.  I began stepping through the moves in the ChessBase analysis to see if
>there was something Chessmaster missed.
>
>It appears to me, and I am quite possibly the worst player who frequents this
>bulletin board, that the following line shows that Rxg6+ is at best a draw :
>
>27.  Rxg6+   fxg6
>28.  Qg4     Bxf2+ (!)
>29.  Kh2     [ Nxf2 is also shown as a draw by Chessmaster 9000 and Fritz 8]
>29.  ...     Kh7
>30.  Bxf8    Qxc2
>31.  Qg5     [Or Ng5+ is also a draw it seems].
>
>So, where did Chessmaster go wrong?  Or is it really drawn and the analysis done
>by Fritz on the ChessBase site is not accurate?
>
>Roy

After Rxg6, and Qg4 there's no easy or clear win, it seems.

Neurosis 1.7 with 48 MB hash, on PIII-550 ,

Legal moves: 39   Static score: 3
Ply Score Time     Nodes      Best move and expected line
------------------------------------------------------------
2   144   6        1632       Rg4 Re8
3   144   6        2280       Rg4 Re8 Rxh4
4   145   22       12138      Rg4 Rd8 Rxh4 gxh5
5   145   77       42829      Rg4 Rd8 Rxh4 gxh5 Rxh5
6   136   341      191858     Rg4 Rd8 Rxh4 gxh5 Rxh5 Bb7
7   96    939      588114     Rg4 < - > Be7 Bxf8 Kxf8 Ng5 Qc4 Ne6+
7   68    1060     654914     Rg4 Be7 Bxf8 Kxf8 Bb1 Qc4 Ng3
8   68    3087     2004280    Rg4 Be7 Bxf8 Kxf8 Bb1 Qc4 Ng3 Qxc3
9   28    6591     4389387    Rg4 < - > Be7 Bxf8 Kxf8 Bb1 Qc4 Ng5 gxh5 Ne6+
9   0     17549    11486278   Rg4 Be7 Kh2 Rd8 Kh1 Kh7 Bb1 Qb3 Qxb3
10  -4    61868    44551811   Rg4 Be7 Kh1 Rd8 Rg3 Bb7 Ng7 Kh7 Qc1 Kg8
11  1     186686   134109972  Rg4 Be7 f4 Re8 f5 Nf6 Nxf6+ Bxf6 Kh1 Qb2 Qd2
11  2     324275   221918283  Re3 < + > gxh5 Qxh5 Qa1+ Kh2 Nf6 Qxh4 Bxh3 Kg3 Bf5
11  2     439558   308182882  Re3 Re8 Ng3 Bb7 Ng5 Ra8 Qd2 f6 Kf1
Total nodes:532725056 n/sec:73400  (Q-nodes:23% max depth:26)

Then, after forcing Rxg6 ,

Legal moves: 3   Static score: -126
Ply Score Time     Nodes      Best move and expected line
------------------------------------------------------------
2   194   0        157        fxg6 Bxf8
3   194   0        905        fxg6 Bxf8 Nxf8
4   200   6        3619       fxg6 Bxf8 Nxf8 Bb1
5   202   22       12052      fxg6 Bxf8 Nxf8 Bb1 Qb2
6   191   203      160660     fxg6 Qg4 g5 Bxf8 Qxc2 g3
7   230   357      254555     fxg6 Bxf8 Kxf8 Ng3 Ke8 Ne2 Bb7
8   239   2411     1917699    fxg6 Qg4 g5 Bxg5 Bxg5 Qxg5+ Kf7 Qc1
9   250   7212     5535842    fxg6 Qg4 g5 Qd1 Rf7 Bxg5 Bxg5 Nxg5 Rf8
10  248   25332    20372997   fxg6 Qg4 g5 Qd1 Rf7 Bxg5 Bxg5 Nxg5 Rf8 Qe2
11  256   65532    50117451   fxg6 Qg4 g5 Nxg5 Bxf2+ Kh2 Qxc2 Bxf8 Kxf8 Qf5+ Ke8
Qf7+
12  216   147986   114172005  fxg6 < - > Qg4 g5 Nxg5 Bxf2+ Kh2 Nxe4 Bxf8 c6 dxc6
12  201   417818   335779179  fxg6 Qg4 g5 Nxg5 Qxc2 Nf3+ Kf7 Nxh4 Qxe4 Qg7+ Ke8
Qxf8+

Doesn't find anything, and keeps giving black a big score.
If there is a win, it's extremely deep..

Stan



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