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Subject: Re: Why?

Author: Slater Wold

Date: 00:39:35 04/15/02

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On April 15, 2002 at 03:35:07, Slater Wold wrote:

>[D]2r4k/1p3p1p/1pn2q2/1N1p1p2/8/PP2Q2P/5PP1/2R3K1 w - - 0 26
>
>Why in this position is it not perfectly clear that taking the pawn (Qxb6) is
>the obvious move?  Instead I've noticed several programs wanting Qf4, a4, and
>other moves that to me, just seem to waste time.
>
>I've spoken with one GM, (2550ish) and he agreed that Qxb6 is the only move that
>he would emphasize on.  (It was a quick discussion, no detail.)
>
>This is move 26 of game one in the first match between Deep Blue and Kasparov.
>Deep Blue played Qxb6 and later won the game.
>
>
>
>**I've tested only a few "top commercial" programs.  Most want Qf4, a4 and
>others at first, and around 1:30 want Qxb6.  My question was, why isn't this
>obvious from the start?**


Actually, I found a program that's it IS pretty obvious to; Crafty 17.7!

              clearing hash tables
              time surplus   0.00  time limit 1:00 (1:00)
         nss  depth   time  score   variation (1)
                7     0.23   0.60   1. Qxb6 Qe7 2. Qc5 Qxc5 3. Rxc5 Rd8
                                    4. Nc7 Ne7
                7->   0.30   0.60   1. Qxb6 Qe7 2. Qc5 Qxc5 3. Rxc5 Rd8
                                    4. Nc7 Ne7
                8     0.52   0.70   1. Qxb6 Qe7 2. Qc5 Qxc5 3. Rxc5 Rd8
                                    4. Nc7 Ne7 5. Kh2
                8->   0.67   0.70   1. Qxb6 Qe7 2. Qc5 Qxc5 3. Rxc5 Rd8
                                    4. Nc7 Ne7 5. Kh2
                9     2.91   0.49   1. Qxb6 Rg8 2. Qc5 Qg5 3. g3 f4 4.
                                    Nd6 Ne5 5. Qxd5 <HT>
                9->   3.37   0.49   1. Qxb6 Rg8 2. Qc5 Qg5 3. g3 f4 4.
                                    Nd6 Ne5 5. Qxd5 <HT>
               10     4.90   0.49   1. Qxb6 Rg8 2. Qc5 Qg5 3. g3 f4 4.
                                    Nd6 Ne5 5. Qxd5 fxg3
               10->   8.60   0.49   1. Qxb6 Rg8 2. Qc5 Qg5 3. g3 f4 4.
                                    Nd6 Ne5 5. Qxd5 fxg3
               11    13.49   0.45   1. Qxb6 Rg8 2. Qc5 f4 3. Nd6 f3 4.
                                    g3 Nd4 5. Re1 Rxg3+ 6. fxg3 f2+ 7.
                                    Kf1 fxe1=Q+ 8. Kxe1
               11->  21.64   0.45   1. Qxb6 Rg8 2. Qc5 f4 3. Nd6 f3 4.
                                    g3 Nd4 5. Re1 Rxg3+ 6. fxg3 f2+ 7.
                                    Kf1 fxe1=Q+ 8. Kxe1
               12    38.86   0.35   1. Qxb6 Rg8 2. Qe3 f4 3. Qf3 Qe5 4.
                                    Rc5 Rd8 5. Kh2 Rd7 6. Kg1 <HT>
              time=1:00  cpu=99%  mat=-1  n=46245754  fh=91%  nps=766165
              ext-> checks=1900898 recaps=106933 pawns=15636 1rep=257959 thrt:14
995
              predicted=0  nodes=46245754  evals=9694671
              endgame tablebase-> probes done=0  successful=0
              hashing-> trans/ref=30%  pawn=99%  used=88%


However, I cannot see the first 6 ply.



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