Could a human see this?

Thanks moonbus, yeah that's the one I got also... it would be remarkable if a human could spot that mate.

It was pretty silly of him to even comment, I definitely wasn't asking for help, but the whole thing just unnerved me.
I'll consider reporting him, for sure.

Originally posted by 64squaresofpain
I had played a few games vs. a seemingly strong player on another site (avg rating above 1900)
and he tells me that I was looking good in one of my other games,
and even suggested it was "mate in 10 or 11 moves if you find the right continuation".

I was surprised, not just because he thought he had seen mate but for the specific number of moves ...[text shortened]... clined playing any more games vs. this person.

(Incidentally, can anyone here find the mate?)

Actually I am probably a real Noob since I assumed that it was a mate in about 6:
1. Rxh6 Rf6 (to make an escape hole for the King).
2. Qh7+ Kf7 (using same hole)
3. Bxf6 Rg8 (the Bishop can't be taken and Qxg7 would be mate if g7 was not protected)
4. Bxg7 Rxg7
5. Qf5+ Kg8
6. Re8#

Something is eluding me here...
On the engine use I would go with GreenPawn and assume that the box only came into play when the position was desparate...

Edit: The stockfish solution with Rf5 was one of the things that eluded me...so my solution is not the best (and probably there are other surprises, but then there is a reason I am no master).

Originally posted by Marinkatomb
I suppose if he was using an engine it could announce mate in 11, but do you think you would have achieved a position with mate in 11 against an engine?

I'll be honest with you, i looked at that position and saw three mates right away. Black must move the rook on f7, it is the only move that avoids mate in one (you can move the f8 rook and prolong the ...[text shortened]... u deliver mate or not is irrelevant, both rooks are falling and the king is running defenceless.

In fact I think any move of the rook will open the escape hole...

Unless the other person was not supposed to do so, how do you know he or she did not use a program to find the win to start with?

Originally posted by Ponderable
In fact I think any move of the rook will open the escape hole...

Rf5 is important not only to open an escape hole, but also to block the queen's diagonal to h7. Of course, it opens another diagonal and merely postpones the mate. Still, it would be quite a feat for a human to see the whole line OTB, and quite improper during a game to mention that there is a mate in x-many moves. If it was a spectator who said that, he was a) showing off, b) a kibbitzer, c) all of the above.

Rxh6 ..Rf6 Qh7+ ..Kf7 Rxf6 is checkmate.

Rxh6 ..Rf5 (to block the Queens diagonal) is really the only try. All other moves allow a quicker mate..

Originally posted by 64squaresofpain
Yeah, let's just be clear that the guy who i was playing against in the "mate in 11" game is not the person i'm suspecting of cheating.
This person was maybe even trying to be helpful, saying "go on, you got 'im! It's mate in 10 or 11" (maybe it was 10 and a half moves?)

Sure there's no real harm in using a box for other people's games as a spect ...[text shortened]... ter moves, saccing pieces unnecessarily etc.
I'm gonna try and make a PGN to show the sequence.

He definitely should not have told you about the mate until after the game. However I don't think that the queen sac is anything but entirely necessary. Black has to do something about the mating threat on h7, but cannot keep his rook off the back rank. In moonbus' line if black does not sac the exchange of queen for rook white has something like: 3. ... Rf5 (blocking the queen again) 4. Qe6+ R8f7 (4. ... R5f7 5. Qg6) 5. Qe8+ Rf8 6. Qg6 Qc7 (6. ... R8f7 7. Qh7+ Kf7 8. Qh8#.) 7. Qh7+ Kf7 8. Qxg7#. I think that once black's seen the Rf5 idea the queen sac isn't that hard to find. So my feeling is that it is at least possible that the player worked this out without a machine, if he's into problems then he could quite easily have seen all that. Besides, except that he commented, it's not his game so he wouldn't be cheating using an engine. If you suspect him of cheating download some of his games against strong opposition and do the analysis.

Originally posted by 64squaresofpain
The actual sequence though, to me, is not so easy to see, certainly not all at once, even including an analysis board.
I tried this, following Rxh6, but could not find a mate like how he said.

I consider you a strong player, could you honestly see mate in 11 moves after Rxh6?
I understand a master probably could, perhaps without too much difficu ...[text shortened]... eat me all too convincingly in our games, barely doing anything wrong, just seemed fishy is all.

Does fritz say 1...Rf5 is the best move?

2.Qc4+ R5f7(can't move the other rook) 3.Qe4 and white has same threat with more centralised queen.

I don't think it would be too hard to find mate as the tree would be very shallow. Black has very few resources to answer mate in 1.

Edit: I just saw someon already posted the best continuation. Yes, that mate shouldn't be difficult to find but I seriously doubt any human would attempt to calculate that far... After the first couple of moves it is clear that black is lost.

You can stop at the Queen sac. We are 150 years removed from the days when someone would announce mate in 11. This is like an exercise in Chess tempo where you do some deep human analysis to solve a tactic and the response by the site is to sac a queen into a hopeless material deficit because the comp can see the mate.