Author: David Dahlem
Date: 19:15:04 04/19/01
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On April 19, 2001 at 21:58:19, Vincent Diepeveen wrote: >On April 19, 2001 at 04:52:09, David Dahlem wrote: > >>I would like to put together a tough test suite of positions where there is only >>one move that will win. Any positions with the solution or suggestions on where >>i might find such positions would be greatly appreciated. >> >>Dave > >Ah a cool try. the problem is that to make such a testset that >you can't already use too well known material as that's already >inside testsets :) > Thanks Vincent Yes, i'm sure there are lots of positions with only one move that will win inside current test suites. But i am not expert enough to separate them from positions with more than one move that will win, if that makes any sense. :-) Dave >But i'll give you 2 tactical positions for free > >Diepeveen - H.H.Hage correspondence game >2rr2k1/pp3pp1/4b3/2qNp1b1/4P3/1B1Q4/PPP5/1K3R1R w - - Qf3!! > >Forgot what year i played this. Some progs have real problems with this one. >If they play it usually compu's play it even for wrong reason. Takes >real HUGE search depths to get score for diep +2.0 for white or so here. > >Mainline and how game went: Qf3!! Rc6 Qh5 Bh6 Qxe5 Bxd5 >Bxd5! Qxc2+ Ka1 Rc7 a3! b5 Rxh6! gxh6 Qf6 1-0 > >Reason why black plays the same moves as the compu's think it plays >is easy. H.H.Hage clearly played this game with a computer... ...i >assumed chessmachine schroeder or something as that could reproduce >all his moves this game! Note that in those days i figured out >myself easily that Qf6 won. Only later programs started showing me >that Rg1 also wins for white. When i played the game the only program >finding that Rg1 won was The King! All other programs didn't find it. >Diep in those days was only an interface, not a chessplaying program >yet :) > >Another cool position but probably easier for some programs and >nearly impossible for others is the next position: > >Analysis of Diepeveen + De Haan >r1b1k2r/p2n1ppp/1p2p3/3p2B1/P2P4/1Nn1P3/5PPP/R3KB1R w KQkq - f3!! >f3 wins a piece. It's not just 0.01 better or so. the piece at c3 >is completely hung. It's not a real fair position as it's an anti-nullmove >position actually. Progs not nullmoving or extending threats will >find this quick and others will need huge depths because of nullmove. > >Try this one at tiger or rebel... ...they might also suffer >from forward pruning here... > >Another cool one which is very simple for some programs as their >evaluation is optimistic about doing it, others dislike it and >will never play it, as the real tactical trick is so deep that >all progs miss it. So this one is no good >in computer testsets but it's a cool combi simply: > >4qrk1/3nppb1/R1Np2p1/3P2P1/1Pr5/4B3/5Q1P/5R1K w - - 4 30 Ra8!! >Benjamin - Xu Jun 2001 >Alexandre Come brought this move into my attention. Took >me some long analysis to realize how bigtime Ra8 wins here... > >For computers to consider they solved it they should get +4.0 or >more for Ra8. >All other scores are in the positional range as white is already >cool passer up. > >I doubt any program will show soon Ra8 with over +4 as the trick is >real deep and it's a matening trick again, so programs which do not >do mating extensions will perhaps never get Ra8, not even at 20 ply >if their positional evaluation says it's not ok to play.
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