Author: Les Fernandez
Date: 12:45:06 02/28/02
Go up one level in this thread
On February 28, 2002 at 15:33:47, Dann Corbit wrote: >On February 28, 2002 at 15:00:03, Les Fernandez wrote: > >>[D]8/4b1k1/R5pp/2p1pp2/1pQq4/1P1P3P/1P3PPK/8 w - - >> >> >>I am interested to know if the above position can be held by black. White is >>short on time but can force perpetual by Qe6. Although a rook is better then a >>bishop, most of the time, should white exchange queens here? I am only an >>average player but after doing a little analysis on this position Crafty reports >>the following on a fairly slow machine. (Pentium 350, 256 mb ram) >> >>8/4b1k1/R5pp/2p1pp2/1pQq4/1P1P3P/1P3PPK/8 w - - acd 15; acn 170618898; acs 900; >>ce 155; pv Kg1 Qxc4 bxc4 h5 g3 Kf7 Kg2 Bf6 Rc6 Be7 Kf3 g5; >> >>Although white is reported to have a 1.55 advantage after Kg1 I wonder if the >>position can be held by black. I also took a look at the position with white >>taking the queen and the ce still appeared about the same with black capturing >>white queen with cxd4. >> >>8/4b1k1/R5pp/2p1pp2/1p1Q4/1P1P3P/1P3PPK/8 b - - acd 17; acn 186582676; acs 902; >>ce -151; pv cxd4 Kg3 Kf7 Kf3 h5 Rc6 Bf6 Rb6 Be7 g3 Bf8 h4 Be7; >> >>Question is with queens off the board can the white rook start chopping up the >>black pawns while the black bishop exists? Can someone run this on better >>hardware and tkae it a bit deeper to see what falls out? > >Despite an evaluation that thinks it is up a full piece, I think it is drawn. > >A bit longer with crafty: > >EPD Kit revision date: 1996.04.21 >unable to open book file [e:\crafty\release/books.bin]. >hash table memory = 48M bytes. >pawn hash table memory = 6M bytes. >EGTB cache memory = 32M bytes. >draw score set to 0.00 pawns. >choose from book moves randomly (using weights.) >choose from 5 best moves. >book learning enabled >result learning enabled >position learning enabled >threshold set to 9 pawns. >5 piece tablebase files found >19045kb of RAM used for TB indices and decompression tables > >Crafty v18.13 > >White(1): hash 300M >hash table memory = 192M bytes. >White(1): st 999 >search time set to 999.00. >White(1): epdpfga \les.epd les.out >PFGA: EPD record: 1 >end-game phase > clearing hash tables > time surplus 0.00 time limit 16:39 (16:39) > nss depth time score variation (1) > 6-> 0.23 2.94 1. Ra7 Kf6 2. Ra6+ Kg5 3. Re6 Qxc4 > 4. bxc4 Bf6 <HT> > 7 0.30 2.88 1. Ra7 Kf6 2. Ra6+ Kg7 3. Qc2 h5 4. > Qe2 Bg5 <HT> > 7 0.40 2.90 1. Qc2 h5 2. g3 Kf7 3. Qe2 Bg5 4. Kg2 > 7-> 0.76 2.90 1. Qc2 h5 2. g3 Kf7 3. Qe2 Bg5 4. Kg2 > 8 0.86 2.89 1. Qc2 h5 2. g3 Kf7 3. Qe2 Bg5 4. h4 > Bf6 > 8 1.81 2.99 1. Kg1 Qxc4 2. bxc4 h5 3. Kf1 Kf7 4. > Ke2 b3 5. f3 > 8-> 1.90 2.99 1. Kg1 Qxc4 2. bxc4 h5 3. Kf1 Kf7 4. > Ke2 b3 5. f3 > 9 2.12 2.90 1. Kg1 Qxc4 2. bxc4 h5 3. f3 Kf7 4. > Kf2 h4 5. Ke3 b3 > 9-> 3.07 2.90 1. Kg1 Qxc4 2. bxc4 h5 3. f3 Kf7 4. > Kf2 h4 5. Ke3 b3 > 10 3.64 2.99 1. Kg1 Qxc4 2. bxc4 h5 3. g3 Bf6 4. > Ra5 Be7 5. Kg2 b3 6. Kf3 > 10-> 5.53 2.99 1. Kg1 Qxc4 2. bxc4 h5 3. g3 Bf6 4. > Ra5 Be7 5. Kg2 b3 6. Kf3 > 11 6.78 3.00 1. Kg1 Qxc4 2. bxc4 h5 3. g3 Kf7 4. > Kg2 g5 5. b3 h4 6. gxh4 gxh4 7. Kf3 > 11-> 10.16 3.00 1. Kg1 Qxc4 2. bxc4 h5 3. g3 Kf7 4. > Kg2 g5 5. b3 h4 6. gxh4 gxh4 7. Kf3 > 12 11.93 2.99 1. Kg1 Qxc4 2. bxc4 h5 3. g3 Kf7 4. > Kg2 g5 5. b3 h4 6. Kf3 Bf6 7. Ke3 > 12-> 26.95 2.99 1. Kg1 Qxc4 2. bxc4 h5 3. g3 Kf7 4. > Kg2 g5 5. b3 h4 6. Kf3 Bf6 7. Ke3 > 13 56.08 3.09 1. Kg1 Qxc4 2. bxc4 h5 3. Kf1 Kf7 4. > Ke2 h4 5. g3 g5 6. Kf3 Bf6 7. Ra5 <HT> > 13-> 1:25 3.09 1. Kg1 Qxc4 2. bxc4 h5 3. Kf1 Kf7 4. > Ke2 h4 5. g3 g5 6. Kf3 Bf6 7. Ra5 <HT> > 14 1:37 3.08 1. Kg1 Qxc4 2. bxc4 h5 3. Kf1 Kf7 4. > Ke2 h4 5. g3 hxg3 6. fxg3 f4 7. Kf2 > b3 8. Ra7 fxg3+ 9. Kxg3 > 14-> 3:57 3.08 1. Kg1 Qxc4 2. bxc4 h5 3. Kf1 Kf7 4. > Ke2 h4 5. g3 hxg3 6. fxg3 f4 7. Kf2 > b3 8. Ra7 fxg3+ 9. Kxg3 > 15 4:36 3.07 1. Kg1 Qxc4 2. bxc4 h5 3. Kf1 Kf7 4. > Ke2 h4 5. g3 hxg3 6. fxg3 f4 7. Ra7 > fxg3 8. Kf3 Ke6 9. Kxg3 > 15-> 9:01 3.07 1. Kg1 Qxc4 2. bxc4 h5 3. Kf1 Kf7 4. > Ke2 h4 5. g3 hxg3 6. fxg3 f4 7. Ra7 > fxg3 8. Kf3 Ke6 9. Kxg3 > 16 12:32 3.10 1. Kg1 Qxc4 2. bxc4 h5 3. Kf1 Kf7 4. > Ke2 Kg7 5. g3 Kf7 6. Ke3 Bg5+ 7. Kf3 > Be7 8. Rc6 h4 9. gxh4 b3 > time=16:39 cpu=100% mat=2 n=541204974 fh=90% nps=541k > ext-> chk=37748306 cap=1678048 pp=342348 1rep=3409275 mate=104978 > predicted=0 nodes=541204974 evals=0 > endgame tablebase-> probes done=0 successful=0 Thanks Dann! So I gather up to this point of an analysis it is not a good idea to trade queens here, interesting. I had a gut feeling about this position as I was pondering it but I ran into the Horizon effect in my brain<s>. It appears that the complication is involved enough for white to force the draw and that was my overall concensus. I spoke to 2 people last night that insisted you swap queens automatically since the bishop is weaker then the rook. I told them in most cases thats true but looking at the black pawns and the squares they are on and location of the kings just didnt sit right with me and it was not obvious how the rook was going to shake that annoying bishop. Oh well thanks again and I will talk to you soon. Les
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