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Up Topic The Rybka Lounge / Test Positions / Not the longest mate ever?
- - By sheepman59 [us] Date 2010-08-07 23:40
http://www.chessbase.com/puzzle/puzz07a.htm

If you click this link, you will find what is supposively the longest mate forced ever in a leagal position. It recently came to my attention that this position is not actualy leagal as black does not have enouph peices for white's pawn structure to result. In case you need clarification; for a pawn to double, it has to take a piece or another pawn. There are not enouph pieces and pawns to create the pawn structure show. So what do you think? Did some chess theorist waste his time creating this position only to have it disproved by an amature?
Parent - - By Athinira (**) [dk] Date 2010-08-09 18:00
Chess positions doesn't have to be possible in a game for them to be puzzle material.

Example:
8/1r6/8/6n1/5k2/1b6/3K3N/7Q b - - 0 0

Mate in 526 moves (from 7 man tablebases, has been posted on these boards before). However, in a real match, the game would be a draw due to the 50 move rule.
Parent - - By sheepman59 [us] Date 2010-08-09 22:25
I know, but this was supposed to be the longest forced mate from a LEGAL position. The genious chess theorist who created this position did not realise that it is not legal and neither did any of the readers of the post on the link.
Parent - - By dcorbit (***) [us] Date 2010-08-10 00:12
"Black does not have enough pieces for white's pawn structure to result:
[Event "Edited game"]
[Site "DCORBIT2008"]
[Date "2010.08.09"]
[Round "-"]
[White "-"]
[Black "-"]
[Result "*"]

1. a4 Nc6 2. Nf3 Nd4 3. Ng1 Nb5 4. axb5 d6 5. b3 Nf6 6. Nf3 e5 7. Ng1 Be6
8. Nf3 Ng8 9. g3 Bc4 10. Bg2 Bd3 11. exd3 d5 12. O-O Qe7 13. Na3 Qb4 14.
Bb2 Qc3 15. dxc3 Bb4 16. cxb4 Rd8 17. Qd2 Rd6 18. Qe3 Rc6 19. Qb6 axb6 20.
Nd4 Nh6 21. Rae1 O-O 22. Nf5 Rc4 23. dxc4 d4 24. c5 Rd8 25. cxb6 c5 26. Nb1
Ng4 27. Nh6+ gxh6
*

I suspect that the position is achievable.  I was easily able to cause white's pawn structure to result.
Parent - - By Uly (Gold) [mx] Date 2010-08-10 01:02
But it's impossible for a light Bishop to get to a2.
Parent - - By dcorbit (***) [us] Date 2010-08-10 19:21
No it's not.  It just has to get there before the pawn advances.
Parent - By Uly (Gold) [mx] Date 2010-08-10 19:33
Oh, true, sorry.
Parent - - By 8lrr8 (***) Date 2010-08-11 00:40
"Mate in 526 moves..."

i thought it was 526 moves before a forced capture (to a 6-piece egtb position that's won)?  meaning the DTM is actually more than 526.
Parent - By Athinira (**) [dk] Date 2010-08-11 07:43
Forced capture in 517 moves, and mate in 526 moves.

If i remember correctly that is.
Parent - - By Ed Collins (*) [us] Date 2012-08-06 03:31
Yes, I'm responding to a post that is almost two years old.

Here's one such way to arrive at the position that was in question:

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]

1.h4 g6 2.h5 gxh5 3.Rh4 Bh6 4.Rf4 Nc6 5.Rf6 exf6 6.g4 Be3 7.fxe3 d5 8.e4
Nh6 9.e5 Bf5 10.e6 Bd3 11.exd3 Nf5 12.Bg2 Qd6 13.Nh3 Rg8 14.Nf2 Rd8 15.Ne4
dxe4 16.Qf3 exf3 17.Bh1 Rg5 18.e7 Kd7 19.e8=B+ Ke7 20.a3 Ne5 21.Ba4 Ng3
22.Bb3 Kd7 23.Ba2 Kc8 24.Nc3 Nc4 25.dxc4 Rb5 26.g5 Qb4 27.axb4 Ne4 28.g6
Nc5 29.g7 Nd7 30.g8=R Ne5 31.Re8 Ra5 32.Re6 Rb5 33.Rb6 axb6 34.d3 Rd7 35.
Be3 Kb8 36.Ne4 Ka7 37.Nd6 cxd6 38.Rd1 Kb8 39.Rd2 Ka7 40.Rg2 Kb8 41.Rg8+
Ka7 42.Rc8 Re7 43.Rc6 bxc6 44.Bf2 Rd5 45.Be3 Kb7 46.Bf2 b5 47.cxb5 Rc5 48.
d4 Rc7 49.dxc5 Kb8 50.b3 Rb7 51.Be3 Rb6 52.cxb6 Kb7 53.Bf4 d5 54.Kd1 Ng4
55.Bb8 Ne5 56.Ba7 d4 57.Kc1 c5 58.Kb2 Kc8 59.Ka3 Kb7 60.Ka4 Kc8 61.Ka5 Kb7
62.Bg2 c4 63.Bh1 c3 *

8/Bk3p1p/1P3p2/KP2n2p/1P1p4/1Pp2p2/B1P5/7B w - - 0 64


I found this question/concern at another website.  A web search then turned up THIS question here.  So there were at least two people who both wondered (doubted) if the position was possible to arrive at legally.   In neither post was proof given.

Thus, I thought I'd take some time to try and come up with a legal set of moves for myself.  At first I couldn't do it... I needed an extra White piece to account for Black's pawn structure.  And then it finally hit me... all I needed was to promote one of White's pawns to give me an extra piece.
Parent - By Bader Al-Hajiri [kw] Date 2012-09-26 04:43
Here's my "Shortest Proof Game" for this position:

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "New game"]
[Black "?"]
[Result "*"]
[PlyCount "70"]

1. a3 Nh6 2. h4 g6 3. h5 gxh5 4. Rh4 d5 5. Re4 dxe4 6. d4 a5 7. Kd2 b5 8. Kc3
a4 9. Kb4 Rg8 10. f4 Rxg2 11. f5 Rg6 12. Bg2 Nd7 13. Bh1 Nc5 14. dxc5 Rb6 15.
cxb6 Be6 16. fxe6 Qd3 17. exd3 O-O-O 18. Bf4 Rd4+ 19. Ka5 Rc4 20. dxc4 c5 21.
Bb8 Kb7 22. Ba7 b4 23. Nc3 bxc3 24. Qd4 cxd4 25. Rf1 Ng4 26. Rf6 exf6 27. Nf3
Bb4+ 28. axb4 a3 29. e7 a2 30. e8=B a1=Q+ 31. Ba4 Qe1 32. Bb3 exf3 33. Ba2 Qe8
34. b3 Qb5+ 35. cxb5 Ne5

I created this in 2002, since 10 years ago! I'm specailist for this kind of positions, Proof Game field.
Up Topic The Rybka Lounge / Test Positions / Not the longest mate ever?

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