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Plunder raids and pruning bad captures
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Ed Schroder



Joined: 18 Aug 2011
Posts: 1615
PostPost subject: Re: Plunder raids and pruning bad captures    Posted: Fri Jun 29, 2012 12:52 pm Reply to topic Reply with quote
hgm wrote:
If people prune bad captures in QS, do they make exceptions for captures with piece that were under attack already?

E.g. when I attack my opponent's Queen, and he would respond with a counter attack on my Queen, the 'obvious refutation' is usually that I make a 'suicide capture' with my Queen. Because when he now recaptures, I take his Queen, making it merely a trade.

So a counter-attack is usually a fatal mistake, but if in QS the suicide capture with the threatened Queen is not searched because it has negative SEE, the program would not see it.

I am especially interested in this, because counter-attacks are often a prelude to a plunder raid, where the attacks are followed by actual captures. Plunder raids can only sustain themselves if each capture of the lagging side targets a new victim at least as valuable as what the opponent threatened with his last capture. (But with pieces as strong as Queen, or even stronger, that is usually possible in multiple ways.) So you are typically in a situation where both sides have a valuable piece under attack, And making the captures is usually not the most effective defense for the leading side. A suicide capture with the threatened piece is much more likely to refute the counter attack, and put an immediate end to the plunder raid.

After loads of experiments a couple of decades back I found that obeying the original idea behind QS was best for me. The goal of QS: check if the eval of a good (above alpha) leaf is safe and the score is reliable. Meaning a QS as fast as possible. For Rebel that meant: winning & equal captures, queen promotions and allow checks in the first 2 plies in QS, all of this in an aggressive lazy-eval setting.

But of course I remain open to all kind of juicy QS extension idea's Wink
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Subject Author Date/Time
Plunder raids and pruning bad captures H.G.Muller Thu Jun 28, 2012 7:51 pm
      Re: Plunder raids and pruning bad captures Daniel Shawul Thu Jun 28, 2012 9:38 pm
            Re: Plunder raids and pruning bad captures H.G.Muller Fri Jun 29, 2012 9:18 am
                  Re: Plunder raids and pruning bad captures Daniel Shawul Fri Jun 29, 2012 11:54 am
      Re: Plunder raids and pruning bad captures Sven Schüle Fri Jun 29, 2012 8:48 am
      Re: Plunder raids and pruning bad captures Ed Schroder Fri Jun 29, 2012 12:52 pm
            Re: Plunder raids and pruning bad captures Vincent Diepeveen Fri Jun 29, 2012 8:02 pm
      Re: Plunder raids and pruning bad captures Vincent Diepeveen Fri Jun 29, 2012 7:55 pm
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