Author: Robert Hyatt
Date: 19:44:00 09/11/01
Go up one level in this thread
On September 11, 2001 at 12:18:52, Uri Blass wrote: >On September 11, 2001 at 10:26:21, Robert Hyatt wrote: > >>On September 11, 2001 at 02:17:09, Uri Blass wrote: >> >>>On September 10, 2001 at 21:27:02, Dave Gomboc wrote: >>> >>>>On September 10, 2001 at 05:56:21, Uri Blass wrote: >>>> >>>>>On September 10, 2001 at 05:02:43, Gian-Carlo Pascutto wrote: >>>>> >>>>>>On September 10, 2001 at 00:48:34, Dave Gomboc wrote: >>>>>> >>>>>>>>>>>>>32.Bg5 Bg7 33.Bf4 c4 34.Re2 Bd7 35.Rd1 Bb5 36.Ree1 Bxa4 37.bxa4 Rb2 >>>>>>>>>>>>>38.Rd2 Rxa2 39.Bxf5 >>>>>> >>>>>>>>>Black has better earlier on: >>>>>>>>> >>>>>>>>>Instead of 36. .. Bxa4 first 36. .. Nd3! >>>>>>> >>>>>>>It looks like White also has better earlier on: >>>>>>> >>>>>>>36.Bxe5! Nxe5 >>>>>> >>>>>>Bxe5 captures the knight, so Nxe5 is obviously impossible. I think >>>>>>you are looking at the wrong line... >>>>>> >>>>>>36.Bxe5 Bxe5 is a straight win for black >>>>> >>>>>Dave meant 36.Bxe5 Bxe5 and it is not clear >>>>> >>>>>Here is again the relevant analysis(I added * to singular moves of black that is >>>>>before move 39 and I am going to look at this position more today because I have >>>>>other things to do) >>>>> >>>>>Thanks to dave Gomboc for doing the job. >>>>>I did not look at most of the analysis for 37...Bxh2+ >>>>> >>>>>36.Bxe5! Bxe5* 37.Nc5! Bxh2+ 38.Kxh2 dxc5* 39.a4 Bc6* 40.Rd6 cxb3 41.Bd3 b2 >>>>>42.Re1 b1Q 43.Rxb1 Rxb1 44.Bxb1 is unclear, while after 40.Re6 Kf7 41.Rde1 cxb3 >>>>>42.Bd3 Bb5 43.axb5 Rxe6 44.Bc4 Rbb6 45.Bxb3 White should be able to hold the >>>>>rook ending. Meanwhile, 40.Re6 Kf7 41.Rde1 Rxd7 42.b4 cxb4 43.cxb4 Rb7 44.Bd1 >>>>>Rxb4 45.Bf3 Bxf3 46.Rxa6 Rb2 is wild!, I'll let someone with a faster machine >>>>>handle that variation (there may be good deviations for either side along the >>>>>way too). If something refutes this line, it's probably this. >>>>> >>>>>This leaves 36.Bxe5! Bxe5* 37.Nc5! dxc5 38.Rxe5 Rxa2* 39.bxc4 Bxc4 40.Rxc5 which >>>>>looks like White should be able to grovel a draw here too. >>>>> >>>>>39...Bc6 40.Rxc5 Bxg2 may be an improvement for black and I did not check this >>>>>line >>>>> >>>>>Uri >>>> >>>>I think more of the moves are singular than you are giving credit for. For >>>>instance, 38.Kxh2 is an obvious case (though perhaps you were counting that as a >>>>normal recapture-extension). >>> >>>I count only black moves and I did not count moves after move 39. >>> >>>Uri >> >> >>If we are talking about SE, then both sides can be extended. > >I counted only black moves for the analysis. >It was not to discuss about their singular extensions. > >There was a claim that white can draw the position and singular lines for black >are lines that you do not need to search for improvements for black. > > You have to take >>their output, ie 11(6) and use that "11 plies" as a starting point. > >11(6) may be relevant for the deeper blue games but not for this game because it >was Deep thought game and I understood that Deep thought searched only 10-12 >plies+singular extensions > > Each >>singular move adds 1 ply to that. Note that a move can be both singular and >>out of check, and it gets extended by 2 plies. Their only extension constraint >>was that two consecutive plies could not extend more than 2 plies total. IE if >>you extend twice at ply N, then you could not extend by 1 on both the previous >>and next moves (before and after that 2-ply extension ply). >> >>That kind of search can probe _very_ deeply in the right lines since SE was >>not their _only_ extension. It was generally "in addition to" everything else >>we all normally do. > >With all these extensions their search depth should be enough to see draw by >repetition or material equality against kasparov at game 2 of the match. I don't see how. That draw is some 60 plies deep. I don't think any program can search to a depth of 60 plies, following checks like that. The size of the tree is enormous, even at 200M nodes per second. > >Almost all the plies that you need to see there are singular moves. >The fact that they did not see the draw suggest that they did extend 1 ply for >every singular move. Note that you don't know that a move is singular until you do a _bunch_ of searching on it. The test is not free at all... > >Uri
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