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Subject: Re: WAC #2

Author: Anthony Cozzie

Date: 19:10:42 05/01/04

Go up one level in this thread


On April 30, 2004 at 23:04:24, Andrew Wagner wrote:

>Here's the position:
>
>[d] 8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - -
>
>The move to find here is Rxb2. My question is...what ply does your program find
>the solution on? To tactically work it out to see that you can force queening
>requires something like 13 or 14 ply. This is an interesting knowledge vs.
>search position...can you special-case this somehow to find it sooner? The
>problem is, as an FM friend of mine pointed out, if the king were just a bit
>closer, the sac is losing. E.g. In this position:
>
>[d] 8/7p/5k2/5p2/p1p2P2/Pr1p1K2/1P1R3P/8 b - - (white pawn missing on e3)
>...the sac would be losing because the king is close enough to stop the pawns.
>So my first inclination to somehow make the static eval see that the pawns were
>worth being down a pawn seems to be bad. Any thoughts?

Zappa needs 14 ply.

If you absolutely must have WAC#2, add passer extensions (extend on push to
7th).  I used to get it in 10-11 ply.  However, I would strongly advise you to
worry more about games then test sets.  If you add too many extensions, your
brute force depth goes down and your program's positional performance suffers.

1... c4-c3 2. b2xc3 Rb3xc3 3. Rd2-a2 Rc3-c2 4. Ra2-a1 Rc2xh2 5. Ra1-d1 Rh2-h3 6.
Kf3-f2 d3-d2 7. Rd1xd2 Rh3-h2 8. Kf2-e1 Rh2xd2 9. Ke1xd2
 = (1.37)	Depth: 14/27	00:00:01.06	1083kN
1... Rb3xb2 2. Rd2xb2 c4-c3 3. Rb2-b6 Kf6-g7 4. Rb6-b7 Kg7-g6 5. Rb7-b6 Kg6-h5
6. Rb6-f6 c3-c2 7. Rf6xf5 Kh5-h4 8. Rf5-f6 h7-h5 9. Rf6-c6 d3-d2 10. Rc6xc2
d2-d1=Q 11. Rc2-e2
 = (3.44)	Depth: 14/27	00:00:02.56	2936kN
1... Rb3xb2 2. Rd2xb2 c4-c3 3. Rb2-b6 Kf6-e7 4. Rb6-c6 c3-c2 5. Kf3-f2 d3-d2 6.
Rc6xc2 d2-d1=Q 7. Rc2-c7 Ke7-e6 8. Rc7xh7 Qd1-c1 9. Kf2-e2 Qc1xa3 10. h2-h4
Ke6-d5 11. Rh7-d7 Kd5-e4
 = (4.91)	Depth: 17/33	00:00:16.71	19773kN

anthony



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