Would Black Win this endgame (if my opponent didn't time out)

Oh, I see you have progressed in the discussion of this ending while I did my analysis I hope it is still of some value to you...

Black wins! 1.Re8 is the toughest defence. Mate in 26 after 1.Re8 by 1...Kf5 (on 1...Kd6?! 2. Rd8+ ! and black can still mate in 27 by 2...Ke6; even 2..Ke5 mates but in 38 moves now :) ( Other moves after 1..Re8 except there two, only draw) (fed the positions into lokasoft tablebase server for above) Against other black moves it is ean easy win for white, of course.:Rd7 gets easily mated in 4, Re6+ gets easily mated in 3, others get mated in 1.) 1. Re8 Kf5 2. Re7 Qg2 (Qf2 wins equally fast; Qh5 takes a move more) ... hell my HD crashed - ive located my tablebase DVD now and post a perfect-play mate soon - doing this by feeding moves one-by-one into the tablebase server is painful!

Norma Jean: Thanks much! It is always nice when the moves on my small handheld board and the conclusions I reach match up with the silicon beasts!

hey, ozzie you are the NM - i am just a connoisseur! Anyway here is a perfect-play mate ( "!" indicates unique move to prolong/hasten mate for w/b resp., "!!" indictes a "!' move [by white here of course] which is flying-rook move (R moves away from K's protection - impossible to find regularly by humans ]) 1. Re8+! Kf5! 2. Re7! Qg2 3. Rg7! Qh1 4. Ke8 Qc6+! 5. Kf8! Kxf6!(so, the P can be safely picked up fast.) 6. Rf7+! Ke5 7. Re7+! Kd6! 8. Rf7! Qh1 9. Rg7 Qh6 10. Kg8 Qe6+! 11. Kh8 Qe3 12. Kg8 Ke6! 13. Kf8 Qf2+ 14. Kg8! Qd4! 15. Rg6+! Kf5 16. Kh7! Qe4! 17. Rg7! Kf6+! 18. Kh8 Qh1+ 19. Kg8! Qh5! 20. Rg1!! Qd5+ 21. Kh7! Qe4+! 22. Kh8 Qa8+! 23. Kh7! Qa7+! 24. Kg8! Qxg1+! 25. Kf8! Qg4 26. Ke8 Qc8# (only move number 20 is a flying-rook move.)

Arsène Lupin strikes again. ;)

Someone who is fast at diagramming pgns might diagram the above - but the only point of interest here is picking up the P safely - Q v R against tablebse defence is not the topic here - anyway this is one of the easier examples of the latter, perhaps. [me - pgn's fine with me - i just copy and paste into a text file and play it through almost anything - usually winboard unless it is a full-fledged pgn file ie with bracketed variations within bracketed variations etc -winboard cant handle variations so then i use any of the other stuff - as you all do ..] I suppose that's it.

;) anyway the prev post must make likesforest happy 'cause i admitted i was somewhet off topic - the point being picking up the pawn :)

normajeanyates' "perfect play" mating sequence:

it's a win, but black has to be careful:

1. Re8+ Kxf6?? 2. Re6+! Kxe6 STALEMATE

Thanks again everyone!  I knew I it would be tricky, but a win for black.

In the perfect play sequence, 25...Qg7+ mates just as fast. 25...Qa7 mates in the same number of moves, but covers more squares (important when time is expiring).

GreenLaser, it would be funny if the tablebases were recomputed with such an extra caveat. I also found it a bit weird that the tablebase answer for black's 25th move would be ...Qg4.

ozzie, it would be funnier if a 26 move mate were longer than a 28 move mate in terms of the time it takes to make the moves.

long tablebase sequences are always stupid! :)

But in the initial position if you capture the pawn safely you are almost home [*] and the tablebase sequence i (or nalimov+crafty) gave for safe P-capture is only 5 black moves and is decent enough...

 the crafty version i used looks slightly broken - eg it shouldn't have "!"-ed 25..Qg4  as there are other moves that mate as fast; as NM GreenLaser pointed out.

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[*] at least again humans [with decently un-short time controls, and moveblocks or fischerincerments!] - unless the human is John Nunn or someone who specialises in studying tablebases to try and extract human-understandable plans from them ...

 

For a recent reference to the idea of playing moves considering the distances to the clock and squares see the video of Zatonskih's Armageddon win against Krush for the US Women's Championship at chessbase.com

NM GreenLaser thanks for the reference! HILARIOUS!!

Is this the beginning of the merging of chess and table-tennis* ?

[US ppl if confused: table-tennis = ping-pong] 

 

If white do the right and also black, then is a draw. Any tiny little mistake in one side is win for the other. Thanx fo posting it was an interesting analysis...

leonelcm> If white do the right and also black, then is a draw. Any tiny little mistake in one side is win for the other.

Err, no, it's a tablebase win--although somewhat complicated for humans. See normajeanyates' message and my follow-up diagram. :)

normajeanyates wrote:

NM GreenLaser thanks for the reference! HILARIOUS!!

Is this the beginning of the merging of chess and table-tennis* ?

[US ppl if confused: table-tennis = ping-pong] 

 

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 edited above post - reposting also

likesforests wrote:

leonelcm> If white do the right and also black, then is a draw. Any tiny little mistake in one side is win for the other.

Err, no, it's a tablebase win--although somewhat complicated for humans. See normajeanyates' message and my follow-up diagram. :)

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 Slight correction - *white's* play (flying rook defence) is somewhat complicated for humans. *black's* strategy (of winning against flying rook defence) - though not in the tablebase way i showed of course! - was already known to humans by 1992. (K+Q v K+R was one of the first tablebases made - by Ken Thompson of course - thats how the frd was discovered - but human strategies to beat it were soon found). By now a majority of IMs - and definitely almost all GMs - know it. All FMs could master winning Q v R against tablebases if they spent a week learning it and practicing it (hell i plan to learn it - it is describable in 1 page --- search rec.games.chess for Roger Poehlman's 1992 post and you can find it.) Masters planning to play official/demo game against a computer learn it as part of preparation if they havent learnt it already.

 It is much simpler than the troitsky (two N's v P with P behind troitsky line) - in the 1940s one USSR GM reached it twice and failed to win both times - USSR chess team captain - the legendary Mikhail Botvinnik - suspended him from further official play until he had leaned it - in a fortnight he did - botvinnik tested him and reinstated him.

[tablebases have found that in some cases the troitsky is a win even with the pawn ahead of the troitsky line, but it is beyond humans to win those *ultra-troisky* positions against computers.]