Author: Bernhard Bauer
Date: 06:28:29 09/15/05
Go up one level in this thread
On September 15, 2005 at 07:36:24, Uri Blass wrote:
>On September 15, 2005 at 07:21:19, Ed Schröder wrote:
>
>>On September 15, 2005 at 06:43:22, Gian-Carlo Pascutto wrote:
>>
>>>On September 15, 2005 at 06:26:30, Ed Schröder wrote:
>>>
>>>>On September 15, 2005 at 04:30:38, Mark Young wrote:
>>>>
>>>>>On September 14, 2005 at 17:05:59, Ernst Walet wrote:
>>>>>
>>>>>>Because Zappa 1.1 is SMP and 64 bit, I gave it a try and was pleasant suprised.
>>>>>>One of my favourite chess positions is this one, where Kasparov played Rxd4.
>>>>>>How do other engines do? If your engine finds it please give it a couple of more
>>>>>>plies to see if it holds it.
>>>>>
>>>>>The better test for the engine in this position, is to see when the program see
>>>>>that Rxd4 is not winning. Since Rxd4 is only a draw with best play.
>>>>>This is why many programs will not play Rxd4, or drop the move with a longer
>>>>>search.
>>>>
>>>>1. Rxd4 cxd4 2. Re7+ Kb6 3. Qxd4+ Kxa5 4. b4+ Ka4 5. Ra7 Bb7 6. Rxb7 Qxd5 7. Rb6
>>>>1-0
>>>
>>>I always thought that simply 1. .. Kb6 was never refuted?
>>
>>You are absolutely right, missed that one. But I would like to see the engine
>>that plays 1..Kb6
>>
>>Hmmm...
>>
>>Ed
>
>I believe that 1...Kb6 was discovered by some engine.
>I am not sure if it is the only move for black and a lot of engines are not
>going to play cxd4.
>
>Note that I could prove that 1...cxd4 is bad by retrogradic analysis with yace
>
>Some possible lines that you can use to do it:
>
>
>[Event "?"]
>[Site "?"]
>[Date "????.??.??"]
>[Round "?"]
>[White "New game"]
>[Black "?"]
>[Result "*"]
>[SetUp "1"]
>[FEN "b2r3r/k4p1p/p2q1np1/NppP4/3p1Q2/P4PPB/1PP4P/1K1RR3 w - - 0 1"]
>[PlyCount "2"]
>
>1. Rxd4 Kb6 (1... cxd4 2. Re7+ Kb6 3. Qxd4+ Kxa5 (3... Qc5 4. Qxf6+ Qd6 5. Be6
>Bxd5 6. b4) 4. b4+ Ka4 5. Ra7 Bb7 (5... Bxd5 6. Qc3) (5... Nxd5 6. Rxa6+) 6.
>Rxb7 Qxd5 7. Rb6 a5 8. Ra6 Ra8 9. Qe3) *
Rxd4 may be the best move, but is not winning.
A better test position would be the position after Rxd4.
[D]b2r3r/k4p1p/p2q1np1/NppP4/3R1Q2/P4PPB/1PP4P/1K2R3 b
Crafty gives
14-> 45.31 -2.17 1. ... cxd4 2. Qxd4+ Qb6 3. Re7+ Nd7
4. Rxd7+ Rxd7 5. Qxh8 Bxd5 6. b4 Re7
7. Kb2 Re2 8. Qc3 Qd6 9. f4 Rxh2
15 1:12 +1 1. ... cxd4
15 1:27 -0.01 1. ... cxd4 2. Re7+ Kb6 3. Qxd4+ Kxa5
4. b4+ Ka4 5. Qc3 Qxd5 6. Qc7 Qd1+
7. Kb2 Qd4+ 8. Kb1 Qd1+
15 7:36 -0.62 1. ... Kb6 2. Nb3 Bxd5 3. Qxd6+ Rxd6
4. Rd2 Rhd8 5. Red1 a5 6. Ka1 Ne8 7.
Bg2 a4 8. Nc1 Bc4 9. Nd3 Bxd3 10. Rxd3
15-> 9:03 -0.62 1. ... Kb6 2. Nb3 Bxd5 3. Qxd6+ Rxd6
4. Rd2 Rhd8 5. Red1 a5 6. Ka1 Ne8 7.
Bg2 a4 8. Nc1 Bc4 9. Nd3 Bxd3 10. Rxd3
So it finds Kb6.
Kind regards
Bernhard
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.