Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: What is the reason that crafty needs 10 plies to find Nf5

Author: Robert Hyatt

Date: 11:05:23 04/29/00

Go up one level in this thread


On April 29, 2000 at 13:29:11, blass uri wrote:

>This position is from the game insomniac0.63-chessmaster6000
>
>[D]6k1/pp2nppp/7r/8/3q4/1P1p1P2/P2P1RP1/RQB3K1 b - - 0 1
>
>Crafty17.10 needs 10 plies to find Nf5 and likes Qh4 with a draw evaluation at
>depth 9 when after Nf5 it needs only 5 plies to see that white is losing.
>
>I know that crafty is a null mover but I thought that null movers do not prune
>more than 3 plies.
>
>Uri


I use R=3 and R=2 depending on depth.  But I do it recursively so it is
possible to lose 5-6 plies in wild sacrificial lines.

In this position, it only takes me 8 seconds to find Nf5 even though the depth
is 10. Score is +13.  By 40 seconds and depth=12, score=+20.

                9->   1.69   0.00   1. ... Qh4 2. Rf1 Qd4+ 3. Rf2
               10     2.32   0.00   1. ... Qh4 2. Rf1 Qd4+ 3. Rf2
               10     8.24     ++   1. ... Nf5!!
               10    36.03  13.18   1. ... Nf5 2. Qc2 dxc2 3. d3 Ng3 4.
                                    Bxh6 Ne2+ 5. Kf1 Qxa1+ 6. Kxe2 Qd1+
                                    7. Ke3 c1=Q+ 8. Kd4 Qxh6 9. Kd5 Qxd3+
                                    10. Kc5 <HT>
               10->  36.04  13.18   1. ... Nf5 2. Qc2 dxc2 3. d3 Ng3 4.
                                    Bxh6 Ne2+ 5. Kf1 Qxa1+ 6. Kxe2 Qd1+
                                    7. Ke3 c1=Q+ 8. Kd4 Qxh6 9. Kd5 Qxd3+
                                    10. Kc5 <HT>
               11    36.20     ++   1. ... Nf5!!
         (2)   11->  41.58  13.57   1. ... Nf5 2. Qc2 dxc2 3. d3 Ng3 4.
                                    Bxh6 Ne2+ 5. Kf1 Qxa1+ 6. Kxe2 Qd1+
                                    7. Ke3 c1=Q+ 8. Kd4 Qxh6 9. Kd5 Qxd3+
                                    10. Kc5 <HT>
               12    41.85     ++   1. ... Nf5!!
               12    49.16  20.07   1. ... Nf5 2. Qc2 dxc2 3. d3 Ng3 4.
                                    Bxh6 Ne2+ 5. Kf1 Qxa1+ 6. Kxe2 Qd1+
                                    7. Ke3 c1=Q+ 8. Kd4 Qxh6 9. Ke5 Qe3+
                                    10. Kd6 Qdxd3+ 11. Kc7 Qxf2 12. Kxb7
                                    <HT>


In this case, I don't mind taking 8 seconds to find this...



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.