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Subject: Gandalf and Crafty tactical problems

Author: Uri Blass

Date: 01:05:15 11/11/00


[D]3r2k1/5p1p/p2p1Q2/1p2pN1P/4p1P1/1b3P2/1q6/3RK1R1 b - - 0 1

Gandalf see a small positive evaluation for black in this position and has
terrible function at depth 9.
The branching factor is clearly more than 10.

Crafty has also terrible branching factor and the only difference is that the
big branching factor is at depth 11 and that the evaluation is 0.00 and not
positive for black.

It did not see a new evaluation at depth 9 after more than 25 minutes on my
pIII450 and I stopped it and did not wait to see evaluation(for comparison
Hiarcs4 see 4.81 pawns against black at depth 8 after only 36 seconds on my
pentium200.

The position is based on the following position

[D]2rr2k1/1b2bp1p/p2p1np1/1p2p1BP/2qNP1P1/5PN1/PPPQ4/1K1R2R1 w - - 0 1

It is from a game between Vescovi and szuhanek

The game continued 1.Ngf5 gxf5 2.Bxf6 Bxf6 3.Qh6 fxe4 4.Nf5 Qe6.

I analyzed the position after 4...Bd5 that is a better move some years ago with
genius3 and found that white is winning by 5.Qxf6 Qxa2+ 6.Kc1 Rxc2+ 7.Kxc2 and
here there is a long line begins with 7...Rc8+ 8.Kd2 Qxb2+ 9.Ke1 Qc3+ 10.Rd2
mate in 14.

4...Bd5 is better move only because white needs more moves to win and computers
may miss the win and reply 5.Rxd5.

Gandalf prefered 7...Bb3+ 8.Kd2 Qxb2+ 9.Ke1 Qc3+ and it does not see that Qc3+
is losing even after more than 20 minutes.

Computers cannot see that 5.Qxf6 is winning because they are weak at tactics and
do not know to extend the right lines and I think that no program of today can
see it but if I am wrong then please tell me if there is a program that find
that 5.Qxf6 is winning.

Here is the relevant position before 5.Qxf6

[D]2rr2k1/5p1p/p2p1b1Q/1p1bpN1P/2q1p1P1/5P2/PPP5/1K1R2R1 w - - 0 1

Uri



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