Author: Amir Ban
Date: 08:16:08 11/18/98
Go up one level in this thread
On November 18, 1998 at 05:00:14, Ernst A. Heinz wrote: >On November 17, 1998 at 06:36:49, Ernst A. Heinz wrote: > >>On November 16, 1998 at 18:19:53, Amir Ban wrote: >> >>>On November 16, 1998 at 14:50:57, Bruce Moreland wrote: >>> >>>>r1r1q1k1/6p1/p2b1p1p/1p1PpP2/PPp5/2P4P/R1B2QP1/R5K1 w - - 0 1 >>>> >>>>It has been contended that this move would be difficult for a computer to find, >>>>and this has caused some doubts to be raised as to whether the computer found it >>>>without assistance in this game. >>>> >>>>I would like to ask how we can clear this up absent input from DB. >>>> >>>>Has anybody run this for a long period on a micro, and if so, was any move >>>>selected other than 35. Qb6? >>>> >>>>Is the counter-attacking line 35. Qb6 Qe7 36. axb5 Rab8 37. Qxa6 e4 supposedly >>>>the reason that white shouldn't play 35. Qb6? Or is it some other line? If it >>>>is too hard or impossible to find 35. axb5, would finding this line show >>>>anything? >>>> >>>>Is there some minimum score delta we can achieve between the position after 35. >>>>axb5 and 35. Qb6 that might be evidence that DB should be given the benefit of >>>>the doubt? >>>> >>>>Are these questions unfair or wrong, if so, are their other questions that can >>>>be asked and possibly answered that will help clear this up? >>>> >>>>bruce >>> >>> >>>This is move 36 but the other details are correct. >>> >>>The first time this was discussed on CCC, Chris Whittington was still here, and >>>he reported for CSTal. It was closer than others, but still couldn't bridge the >>>gap. >> >>I fed this position into the current "DarkThought" yesterday and it liked Qb6 >>with a score of roughly +1.7 up to iteration #18 inclusively. Then, it failed >>low on Qb6 (score <= 1.39) in iteration #19 after processing 6,490,725,565 >>nodes. Currently, it is still engaged in resolving the fail-low (see below). >> >>//////////////////////////////////////////////////////////////////////////////// >> >>r1r1q1k1/6p1/p2b1p1p/1p1PpP2/PPp5/2P4P/R1B2QP1/R5K1 w - - 0 1 >> >># Clearing chess engine. >># Engine sleeps. >>- - >> +------------------------+ >>8 |*R :::*R :::*Q :::*K :::| >>7 |::: ::: ::: *P: | >>6 |*P ::: *B: *P: *P:| >>5 |:::*P ::: P *P: P ::: | >>4 | P :P:*P ::: ::: :::| >>3 |::: :P: ::: ::: P | >>2 | R ::: B ::: :Q: P :::| >>1 |:R: ::: ::: :K: | >> +------------------------+ >> a b c d e f g h >> >>14.01 Qb6 Rd8 Be4 Rac8 Qxa6 bxa4 Qxa4 Qxa4 Rxa4 Rd7 ... (1.71) #62711053 >>15.01 Qb6 Rd8 Be4 Rac8 Qxa6 bxa4 Qxa4 Qh5 Kh2 Qg5 ... (1.69) #140398448 >>16.01 Qb6 Rd8 Be4 Rac8 Qxa6 bxa4 Qxa4 Qh5 Qa7 ... (1.70) #423411650 >>17.01 Qb6 Rd8 Be4 Rac8 Qxa6 bxa4 Qxa4 Qh5 Qa7 Qh4 ... (1.73) #1230726361 >>18.01 Qb6 Rd8 Be4 a5 axb5 axb4 Rxa8 Rxa8 Rxa8 Qxa8 ... (1.64) #3337837066 >>19.01 Qb6 <=178? (1.39) #6490725565 >> >>//////////////////////////////////////////////////////////////////////////////// > >I run this on a 500MHz Alpha-21164a and the fail-low of iteration #19 got >resolved to +1.26 after 14:34 hours and 11,196,023,081 nodes (see below). > >>19.01? Qb6 Rd8 Be4 a5 axb5 axb4 Rxa8 Rxa8 Rxa8 Qxa8 ... (1.26) #11196023081 > >I will let "DarkThought" continue the calculation as long as the other people >at our institute do not get too angry at me for blocking so many Alphas ... :-) > >=Ernst= You are doing well so far. You are following a line that ultimately draws. Last year we analyzed this line here, not through searching from the initial position, but in the old-fashioned way of by suggesting variations and following them through. Someone suggested 36...Rd8 as an improvement to DB's 36...Qe7, and then we hit on the piece sacrifice 38...axb4!! Your line should continue Qxd6 Qa1+ Kh2 Qf1 g3 bxc3 ... Though it appeared like black would be losing in this line, we ultimately analyzed this to be drawn. There is a similarity to the final position (45 ... resigns), though this one's more complicated and even longer. I wrote a post in Oct 97 or so, that summarizes the analysis. It's in the archives if anyone wants to dig it up. Amir
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