Author: Robert Hyatt
Date: 17:47:40 11/10/99
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On November 10, 1999 at 20:32:58, Will Singleton wrote: >r2r2k1/pp3ppp/2n2b2/4p3/2N5/1PP2B2/1P3PPP/R2R2K1 b - - > >This position gives my program fits. Some stronger progs solve it easily. It >appears to be a simple case of extending on captures, and then doing the qsearch >right, which I apparently am not. > >Here's the main line which should be found: >Rxd1 Rxd1 Rd8 Rxd8 Nxd8 Nd6 b6 Nc8 Bg5 Nxa7 Bc1 and gets the pawn back. > >It appears that you need 13 ply to see that the bishop can get the pawn back. >Extending on a capture that brings material back to nominal, there are 2 >extensions in the above main line, so you now need 11 ply. The qsearch reduces >this to 10. And that's what my program needs, 10 ply. Seems too long. > >I would love to find this sooner without blowing up the tree. > >(from a game on ICC today, Postmodernist vs Amateur) There are two ways you have to look at such positions: (1) what is the right move and why is it right? (b) what is the second-best move and why is it wrong? In this position, crafty isn't what I would call "happy". It plays Rxd1 after a second or so on my xeon, at depth=7. But the score is roughly -.6 and it doesn't get better even at depth=12... So it might be some sort of positional mis-judgement you are fighting, rather than not seeing some tactic that looks simple...
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