Author: Laurence Chen
Date: 16:35:30 05/17/99
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On May 17, 1999 at 17:08:06, Francis Monkman wrote: >Analyzing a good number of GM games using a computer, one clearly finds >examples of flawed analysis. On the other hand, one (perhaps as often) >finds examples where it could be said that the computer 'simply doesn't >understand the position', and sees advantage for an already-losing side. >I'm surprised that a strategic principle (ie let your opponent think he's >winning) practised throughout history by human players should prove so >hard (at least at the moment) to conceive against 'the machine'. > >A good, simple example of why never to take computer analysis for granted: > >Play into any engine the following moves: 1. g3 d5 2. Bg2 c6 3. Nf3 Bg4 >4. c4 e6 5. b3 and watch the analysis for a while. I'd be surprised if a >clear advantage to Black isn't registered, probably with ...dxc4 as the >chosen continuation -- most programs would perhaps play this at 40/2? >(Rebel10 no exception, at 200MHz, although the advantage it gives Black >is much less than some programs -- about +0.20. Some register >+1.00.) > >Now walk it through the following: 5. ...dxc4 6. bxc4 Bxf3 7. Bxf3 Qd4 >8. Qb3 and while the analysis of...Qxa1 initially resembles a Rottweiler >with a sausage, most programs calm down after a little and prefer ...Qd7 >or even ...Nd7 (probably best, but still with an excellent game for White). >After 8. ...Qxa1, of course, 9. Qxb7 gives White a clear advantage. > >Well, I suppose that's why we give computers opening books -- but then I >guess we all know Deep Blue shouldn't really have won with a 'look-up' sac. > >[This is from an interesting game, Ubilava-Gurgenidze Tbilisi,1971 [Gufeld], >where Black played 5. ...Nd7 and after a hard struggle with several winning >chances missed by White, Black lost on time with a winning position!] > >Francis Well, what programs are you using to give you >+1.00? Hiarcs 6, Fritz 5.32, Junior 5 give < 0.5 after 5. b3. Of course most chess engines will play 5. ... dxc4, the reason is to open up the game. Remember that chess engines, at least the top 5 SSDF chess engines prefer open games, will want to keep the game open because they excell in tactics. I don't see anything wrong with the choice of 5. ... dxc4 as compared in the actual game in which Black prefer to keep the game in closed channels. Also after the continuation given, there's no obvious reason to show that White has a winning game, White has pressure, but it's not obvious to demonstrate a winning or definetely advantage for White. The game is far from over. Laurence Chen
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