. But it's a good exercise in thinking and the responses are interesting. advantage of moving first - mate in 4 in symmetrical position
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Thank you, point taken Normajeanyates. But I wasn't serious either, especially as there's no such proverb 
. But it's a good exercise in thinking and the responses are interesting.
. But it's a good exercise in thinking and the responses are interesting. 
likesforests wrote:
normajeanyates> But *if* the position is reachable, then getting a proof-game will require or at least be greatly aided by retrochess software
No serious "retro-thinking" is required. I already explained how to setup this position above, "It should be trivial to do, but it would take a long time to line up the pieces to be captured and avoid checks once there are that many queens on board. There are 14 capturable pieces, and you only need 7 captures to clear lines for 7 pawns from each side to promote so you would even have to spend some tempi 'cleaning up' the extra pieces."
I sacrificed 14 minutes of my life to demonstrate (I would probably have otherwise wasted it watching the news anyway!) It could be done in many fewer moves:
That was impressively fast! Hats off! (only I have no hat ... to pre-empt sardonic retort .. except perhaps the one i sometimes talk through ;/ )
[I thought I only talk *chess* better than I play it; now i see that I talk *retrochess* better than I play it, too :) ]
likesforests wrote:
normajeanyates> But *if* the position is reachable, then getting a proof-game will require or at least be greatly aided by retrochess software
No serious "retro-thinking" is required. I already explained how to setup this position above, "It should be trivial to do, but it would take a long time to line up the pieces to be captured and avoid checks once there are that many queens on board. There are 14 capturable pieces, and you only need 7 captures to clear lines for 7 pawns from each side to promote so you would even have to spend some tempi 'cleaning up' the extra pieces."
I sacrificed 14 minutes of my life to demonstrate (I would probably have otherwise wasted it watching the news anyway!) It could be done in many fewer moves:
This is wonderful. I have always wondered whether all pawns can queen in a game....great demonstration (though 7 queens here).
I'm glad it was entertaining. :)
likesforests, I wonder if you could take some time out to construct a "proof game" reaching a position with 18 queens on board (2 original + 16 promoted) - no other condition, so it should be easy for you.
You could also post it on rec.games.chess - that newsgroup has degenerated so - it needs some interesting material; and many ppl who search r.g.c. archives would be interested i'm sure -
or maybe post it on r.g.c and send a link here [but then some readers here don't have pgn viewers so playing through it would be painful for them] - or with your permission, I'll post it [and this one] on r.g.c. - i'll of course credit you, put in keywords so that a usenet search for "18 queens" credits "likesforests" prominently - etc etc ...
Many ppl like me who are above 45 years of age are still wistful about usenet...
[copy messaged to likesforests]
normajeanyates, feel free to post it on r.g.c. I haven't visited there in a loooong time. I wonder if it has changed... I remember Ray Gordon (class A) arguing with IMs that opening theory is everything, Sanny boldly asserting his chess engine can beat any human out there (but it's consistently beaten by r.g.c members), and Sam Sloan's conspiracy theories (which twice a day turn out to be true). ;-)
Thanks a lot, likesforest - i am really grateful.
It wouldn't be too off-the-mark to say that r.g.c. is "finished" - it is overwhelmed with junk that has nothing to do with chess. (I last had a 10-min browse c. 2006-end - gave me a headache. [I've *searched* rgc after that - this year also i think - i remember *two* somwhat-useful short discussions post-2004.] And to think that times were when Susan Polgar occasionally posted on rgc - and the interesting combination of meaningful and paranoid debates involving Bob Hyatt, Chris Whittington (CSTal author) and several other people, etc etc.
But people (at least 45+ers) who want to find some chess stuff usually *also* search rgc - "let's see if there's something on this in the rgc archives also" - eg quick ref to winning with lone Q v lone R, including against tablebase defence - there is a nice 1992 article on rgc [NM roger poehlman] so if someone asks me i refer them to rgc - then curiosities like a 16-move game ending in mutual stalemate - i.e. it would still be stalemate if pass (nullmove) were a valid chess move! And the game is hilariously annotated :)
btw for usenet specially chess i use the handle lqac.waz since 2004 or so.
rec.games.chess appears to be dead but rec.games.chess.analysis is still alive. And Yes, I see Sanny and Ray and Sam in the first 20 posts... some things never change. ;)
Sanny> "Remember Advance level plays better than Rybka So you must analyze for longer hours to give any good reasion. I do not understand how zebediah manages to win Advance in just 35-40 Moves?"
Helpbot> The GetClub program neglects normal piece development in favor of marauding Queen moves. This is a hallmark of most weak /human/ players as well... Yes, the Advance level is probably around 3500--3600 strength now. This is why the 3000-rated Rybka program can only give it Knight or perhaps Rook odds, and no more. With Queen odds I expect the GetClub Advance level would /eventually/ prevail.
yes i know, its been dead since 2003 i think - i meant rgc* :)
i was also about to tell you that rgca seems to have come alive again :)
I posted it in rgca - copy's come to my mail - appeared on rgca yet?
Yep, I see it!
yes -
[I am putting the link here so that it goes on record and works for non-usenetters also]
via google the link is: [concatenate the three lines!]
http://groups.google.co.in/group/rec.games.chess.analysis/
browse_thread/thread/
cbb5f05ef9517c97/5dade4f72ed4995d?hl=en&lnk=st&q=#5dade4f72ed4995d
[tested - done!]
Actually I don't think I am bad at retroanalysis - it is just that retroanalysis is too difficult for this [whaever software aid you use or don't]. Retroanalysis is - what could the last move be? [or in other problems - where must this pawn have come from? Can I show that that R is a promoted one? etc].
normajeanyates> But *if* the position is reachable, then getting a proof-game will require or at least be greatly aided by retrochess software... likesforests> No serious "retro-thinking" is required.
likesforests got the approach right instantly - this needs *no* retroanalysis - that is the wrong tool. It needs a forward construction - start with the standard start position and try to get to that 16-queens mate-in-4 position.
I mean, if someone gives me a "normal" position from a game and asks me to construct *a* game [with legal but maybe horrible moves] that gets that position, I'll of couse not go retro - I'll start at the starting pos and go forward. Extreme example, consider a pos with only the 2 kings left - now retroanalysis wouldn't even come to mind!
As for actually constructing those two games, and so fast, that's sheer genius on likesforests's part!
I would say you have a full box of tools (retro-analysis, etc.), which means you can solve more problems, but you have the dilemma of which tool to use. I only have a hammer so I automatically reached for it and this time it happened to work out. ;)
oh dont be modest - be objective about yourself - like sherlock holmes or hercule poirot ;)
I for my part will remain a female version of Arsene Lupin ;)
Those who read this topic will be surely interested in lydiablonde's excellent puzzle - same abstract idea (symmetry, mate in 4) but totally different theme! --
Thanks a lot, likesforests
btw this mate-in-4 problem is solvable by humans without computer aid! Svante Carl von Erichsen gave an argument narrowing the first move to 2 choices.
[on www.ficgs.com ->problems]
Normajean Yates (2008-07-11 02:41:24)
try this without using a program
<the problem diaagrammed> <ie 4k/qqqqqqqq/////QQQQQQQQ/4k w>
White to play and mate in 4. There is a unique first move. Find it. Make a guess.
[I thought this one up a few years ago - i want to see how difficult it is for humans. Any good program will solve it in a few seconds.]
Svante Carl von Erichsen (2008-07-11 15:26:09)
first move
I think that the first move has to be 1.Qaxf7 or 1.Qfxf7.
Reason: In order to complete the task in 4 moves, we have to keep the king in check, otherwise Black can stall with checks of his own; so, one of the Queens d7, e7, or f7 has to be captured. Capturing e7 results in immediate counter-check, and capturing d7 has no continuation. Also, f7 is the only candidate under double threat.
However, I find no forcing continuation afterwards when the black King just moves to d8.
Normajean Yates (2008-07-11 21:33:22)
that's damn good!
yes, the first move is Qaxf7!. (Qfxf7 doesn't work).
From your response ( :) ) i now feel humans can 'heuristically' conjecture that Qaxf7 begins a mate in 4, while Qfxf7 and others don't.
Normajean Yates (2008-07-11 21:44:53)
The other one fails to:
Qfxf7 fails to Qxf7. No mate-in-3-or-less after that. In fact there is no mate in 4 either.
Normajean Yates (2008-07-11 22:07:23)
but i dont agree with your last sentence
if 1. Qaxf7+ Kd8 2. Qhxc7+ Qbxc7 (only legal move!) 3. Qexe7+ Kc8 (only legal move!) 4. Qdxd7# (or Qexd7#).
On, 1 Qaxf7+ Qgxf7 (the only other legal move) 2. Qh8+! [unique move which gives mate in 3], now 2.. Qxh8 (forced, since the only other move is 2..Qf8 3.Qfxf8# (or 3.Qhxf8#)); now 3. Qxh8+ Qff8 (or Qfg8) 4. QxQ # (choice of two Qs here to mate with).
Svante Carl, now that you have guessed the solution (or narroed it down to two moves), and since the above is quite forcing; so it looks human-solvable to me after all!
Normajean Yates (2008-07-11 22:09:20)
conclusion
Svante Karl and my joint research shows that this problem is human-solvable after all, it seems!
wow likesforests... lol thats impressive in a wierd kinda way...