The Hardest Puzzle Ever Composed

 Strange, my engines finds "mate in 10" at least in 2 ways: Bc2+ and Ne5.

Clearly neither of those moves is mate in 10. Maybe something is wrong with your engine.

Currently my engine finds Nf6+! in about 5-10 seconds and gives white a substantial advantage, although black can hold on for a while with 4... Kg4.

Also, please do not double post, especially when both your posts seem to misinterpret a puzzle.

 Oh, you can't be serious. When I ran this position through an engine it immediately gave Black a significant edge (about 1 pawn), and after 5 minutes or so Black's lead was up to about 1.5 pawns. Also, the suggested "best" move was 1.d8=Q?? ; when I put in 1.Nf6+! the engine actually gave Black 4-pawn advantage! Then after 3.Bc2+! the engine was convinced Black had a won position (the eval. was at 7.0+ in Black's favor). Only after 4.d8=Q did it realize Black was busted; it recommended 4...Kg4 with White better by ~3.2 pawns. 

What engine did you use? 

 My engine finds Nf6+ at first too, but this leads to mate in only 11 moves.

Stop using your Ipad for calculating!

You're right. It looks like what happens was that I input the move for one purpose, then later went back and had it analyze the position. Apparently Rybka takes all prior calculations in that session into account.

Now starting it fresh, it is taking much longer. I'll edit this if it finds the solution in the next few minutes.

E: well it found Nf6+ sometime in the last few minutes (for a total of around 10-15 minutes) after searching 710 million nodes, and it gives white +5.65. That's on Rybka 2.2 64 bit.

You're an idiot.

Well, that's a relief. I was starting to wonder whether the program I used was just broken... or something. But yeah, most engines are the same way; once they've been shown the correct line, they'll instantly find the moves when you return to a previous position.

Oh really? Why don't you just share the whole continuations with us, then? I'd certainly like to see a forced mate in 10 for White that hasn't been found after more than two decades of analysis by the best GMs and problemists in the world, aided by the strongest available computers.

White has to start a shoving match with the opponent, while effectively wiping the blacks king off the board. :)

This took Houdini 50 seconds to figure out on my so-so hardware. Just saying. Hardest move to find ever, it is not. 

Well, I think I found something wrong with the solution to this chess puzzle. I found only two solutions to mate. The first is a 15 move mate and the second is a 29 move mate (both are longer than that posted as the solution)

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[BlackElo "0"]
[Classes "0"]
[ECO "?"]
[FEN "8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - 0 1"]
[SetUp "1"]
[TimeControl "?"]
[WhiteElo "0"]

1. Nf6+ Kg7 2. Nh5+ Kg6 3. Bc2+ Kxh5 4. d8=Q Nf7+ 5. Ke6 Nxd8+ 6. Kf5 e2 7.
Be4 e1=N 8. Bd5 c2 9. Bc4 c1=N 10. Bb5 Nc6 11. Bxc6 Nc7 12. Ba4 Nc2 13. Bxc2
Ne2 14. Bd1 Ne8 15. Bxe2# *

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[BlackElo "0"]
[Classes "0"]
[ECO "?"]
[FEN "8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - 0 1"]
[SetUp "1"]
[TimeControl "?"]
[WhiteElo "0"]

1. Nf6+ Kg7 2. Nh5+ Kg6 3. Bc2+ Kxh5 4. d8=Q 4... Kg4 5. Qe8 Kf3 6. Qh5+
Kf2 7. Bd1 Kg1 8. Qe2 c4+ 9. Kc6 Nc5 10. Qxe3+ Kg2 11. Qe2+ Kxg3 12. Qxc4 Kf2
13. Qxb4 Nce4 14. Qd4+ Kg3 15. Qe3+ Kg2 16. Bc2 Nd2 17. Qxc3 Ndf3 18. Qh8 Nf7
19. Qg7+ N7g5 20. Qxh6 Nd4+ 21. Kd5 Ngf3 22. Bd1 Nh2 23. Qg5+ Kf2 24. Kxd4 Kf1
25. Qg3 Ng4 26. Qxg4 Kf2 27. Ke4 Kf1 28. Ke3 Ke1 29. Qg1

Well, I think I found something wrong with the solution to this chess puzzle. I found only two solutions to mate. The first is a 15 move mate and the second is a 29 move mate (both are longer than that posted as the solution)

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[BlackElo "0"]
[Classes "0"]
[ECO "?"]
[FEN "8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - 0 1"]
[SetUp "1"]
[TimeControl "?"]
[WhiteElo "0"]

1. Nf6+ Kg7 2. Nh5+ Kg6 3. Bc2+ Kxh5 4. d8=Q Nf7+ 5. Ke6 Nxd8+ 6. Kf5 e2 7.
Be4 e1=N 8. Bd5 c2 9. Bc4 c1=N 10. Bb5 Nc6 11. Bxc6 Nc7 12. Ba4 Nc2 13. Bxc2
Ne2 14. Bd1 Ne8 15. Bxe2# *

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[BlackElo "0"]
[Classes "0"]
[ECO "?"]
[FEN "8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - 0 1"]
[SetUp "1"]
[TimeControl "?"]
[WhiteElo "0"]

1. Nf6+ Kg7 2. Nh5+ Kg6 3. Bc2+ Kxh5 4. d8=Q 4... Kg4 5. Qe8 Kf3 6. Qh5+
Kf2 7. Bd1 Kg1 8. Qe2 c4+ 9. Kc6 Nc5 10. Qxe3+ Kg2 11. Qe2+ Kxg3 12. Qxc4 Kf2
13. Qxb4 Nce4 14. Qd4+ Kg3 15. Qe3+ Kg2 16. Bc2 Nd2 17. Qxc3 Ndf3 18. Qh8 Nf7
19. Qg7+ N7g5 20. Qxh6 Nd4+ 21. Kd5 Ngf3 22. Bd1 Nh2 23. Qg5+ Kf2 24. Kxd4 Kf1
25. Qg3 Ng4 26. Qxg4 Kf2 27. Ke4 Kf1 28. Ke3 Ke1 29. Qg1

Accourding to wikipedia the position was epicly easy. You must give me a link to this puzzle cus what I found must have been the wrong one since I solved within 3 minutes and then laughed my ass off at myself for being soo stupid :)

The following is the correct position. Note that in shatrang, the cousellor ("queen") can move only a single square diagonally and you win either by checkmating the king or capturing every other piece.

it was solved by Yuri Averbakh...... thats all i know..........

I've tried a few times to make difficult yet still entertaining chess puzzles, though nothing like the amazing effect of the OP.  Here are two that I like, though I'm not totally sure the final positions are (respectively) drawn/winning.

1. White to play and draw

2. White to play and win

There are far too many mistakes from both sides in both puzzles to solve either of them.

Such as? (assuming that comment was about the puzzles I posted)

I can explain some of the more surprising moves for you, if you like, but I'd suggest perhaps trying to work it out for yourself first.  Note that comps generally misanalyze it for quite some time and some might never solve it, given the confusion they will have about the ensuing endgames (KNN vs Kppp especially).

I would be interested to find out what the fastest way to mate is in the 4...Kg4 line (for the original puzzle). With a computer, I was able to convert the position on move 16 to a queen+king vs. bishop+knight+king endgame, with a mate in 34 for white. So it appears to be a mate in 50, but perhaps a faster mate is possible (or black might have a better defence).

this puzzle is not in type of mate in n#moves puzzles! because black can easily take the white night and run from the dancer beshop!! how? see this:

white is better here..im not agree with those who say no engine can solve this problem! i jus simply gave it to fritz (shout out) and it found the best way of continuation! and now white sees  that black chooses a tricky way for the endgame!

black leaves white with his queen and bishop agains his pawns and pieces!

any chess player know white can hardly win this game!

just give this continuation to your engine and go to analysis/shout out

if computer play for both white and black it leads to k+Q+B against K+N+B+N and this is hard to win for any chess player..but computers know the way  and they win in 30 moves or more!!

its in the forum "Plaskett's Puzzle" am i right?