Author: Uri Blass
Date: 01:31:56 09/05/02
Go up one level in this thread
On September 03, 2002 at 11:43:11, John Merlino wrote: >On September 03, 2002 at 09:29:24, Uri Blass wrote: > >>I am going to put the following positions in my test suite(they seem to be easy >>for the top programs but not easy without the relevant knowledge) >> >>Can you find all the solutions? >>I give a list of candidate moves and I am almost sure that the solutions are >>only from the candidate moves. >> >>[D]8/8/3R2p1/1qb4p/8/p5P1/1pk2P1P/4Q1K1 w - - 0 76 >> >>candidate moves:Rd8,Qe4,Qd1+ >> >>Movei played Rd2+ that is a losing move. >> >>possible line 76.Rd8 g5 77.Qd1+ Kc3 78.Qf3+ Kb4 79.Qe4+ Kb3 80.Qe6+ Ka4 81.Qe4+ >>Qb4 82.Qc2+ Ka5 83.Ra8+ Kb5 84.Qd3+ Qc4 85.Rb8+ Bb6 86.Rxb6+ Kxb6 87.Qxc4 b1Q+ >>88.Kg2 and it seems that white can draw by perpetual check. > >Chessmaster, on a PIII-733, chooses Qe4+ in less than one second, but switches >to Rd8 after 3:24, but it does not show anything close to a drawing score: > >Time Depth Score Positions Moves >0:00 1/3 -2.19 6248 76.Qd1+ Kc3 77.Qe1+ Kb3 78.Qe6+ > Qc4 79.Rd3+ Kb4 80.Qe1+ Ka4 >0:00 1/3 -2.09 9524 76.Qe4+ Kb3 77.Rd2 Qc4 78.Qxg6 >0:00 1/3 -1.97 10258 76.Rd2+ Kb3 77.Qb1 Qc4 >0:00 1/4 -2.19 20192 76.Rd2+ Kc3 77.Rd7+ Kb3 78.Qe6+ > Qc4 79.Rd3+ Kb4 80.Qe1+ Ka4 >0:00 1/4 -1.83 25984 76.Qe4+ Kb3 77.Qe6+ Qc4 78.Rd3+ > Kb4 79.Qe1+ Kb5 80.Qe8+ Ka5 81.Qa8+ > Qa6 >0:00 1/5 -1.83 49824 76.Qe4+ Kb3 77.Qe6+ Qc4 78.Rd3+ > Kb4 79.Qe1+ Kb5 80.Qe8+ Ka5 81.Qa8+ > Qa6 >0:01 1/6 -1.42 115391 76.Qe4+ Kb3 77.Qe6+ Kb4 78.Qe1+ > Ka4 79.Qe4+ Qb4 80.Qe8+ Kb3 81.Qe6+ > Kc2 82.Qxg6+ Kb3 >0:02 1/7 -1.39 198838 76.Qe4+ Kb3 77.Qe6+ Kb4 78.Qe1+ > Ka4 79.Qe4+ Qb4 80.Qe8+ Kb3 81.Qe6+ > Kc2 82.Qxg6+ Kb3 83.Qe6+ Qc4 84.Rd3+ > Kb4 >0:05 1/8 -1.59 481834 76.Qe4+ Kb3 77.Qe6+ Ka4 78.Qe4+ > Qb4 79.Qe8+ Kb3 80.Qe6+ Kc2 81.Qxg6+ > Kc1 82.Qg5+ Kb1 83.Rd1+ Ka2 84.Qd5+ > Qb3 >0:15 2/9 -1.80 1522190 76.Qe4+ Kb3 77.Qe6+ Ka4 78.Qe4+ > Qb4 79.Qe8+ Kb3 80.Qe6+ Kc2 81.Qe2+ > Kb1 82.Rd1+ Ka2 83.Qc2 g5 84.Qb1+ > Kb3 85.Rd5 Qb6 >0:48 3/10 -1.79 4721469 76.Qe4+ Kb3 77.Qe6+ Ka4 78.Qe4+ > Qb4 79.Qe8+ Kb3 80.Qe6+ Kc2 81.Qe2+ > Kb1 82.Rd1+ Ka2 83.Qc2 h4 84.Qb1+ > Kb3 85.Rd3+ Ka4 86.Qd1+ Ka5 87.Rb3 > Qe4 >1:40 4/11 -2.05 10200620 76.Qe4+ Kb3 77.Qe6+ Ka4 78.Qe4+ > Qb4 79.Qe8+ Kb3 80.Qe6+ Kc2 81.Qe2+ > Kb1 82.Rd1+ Ka2 83.Qc2 Bd4 84.Qb1+ > Kb3 85.Rd3+ Bc3 86.Rd8 h4 87.Ra8 > hxg3 88.hxg3 >3:24 4/11 -1.90 19651309 76.Rd8 Kb3 77.Qe6+ Ka4 78.Qe4+ > Qb4 79.Qc2+ Kb5 80.Qd3+ Qc4 81.Rb8+ > Bb6 82.Qd7+ Qc6 83.Qd3+ Kb4 84.h4 > Qb5 85.Qe4+ Kb3 86.Qe6+ Kc3 >7:19 5/12 -1.90 41380792 76.Rd8 Kb3 77.Qe6+ Ka4 78.Qe4+ > Qb4 79.Qc2+ Kb5 80.Qd3+ Qc4 81.Qd7+ > Ka5 82.Qb7 Qb5 83.Qa8+ Qa6 84.Qe4 > Bxf2+ 85.Kg2 Bc5 86.Rb8 Bb6 I believe that chessmaster does not see the chances of white for a draw by perpetual check. If I follow the main line of chessmaster in the first plies I probably get a draw. 76.Rd8 Kb3 77.Qe6+ Ka4 78.Qe4+ Qb4 79.Qc2+ Kb5 80.Qd3+ Qc4 and now 81.Rb8+ Bb6(forced) 82.Rxb6+ Kxb6(forced) 83.Qxc4 b1Q+(forced) 84.Kg2 84...a2 seems to be a draw by perpetual check Black has other alternatives but I doubt if they are enough for a win. Uri
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.