*groan* Very Original!! 

easy. took me less than 5 seconds. mostly because others have posted same kind. but thanks for posting a different set-up.

Yeah, I wanted one that required a touch of retrograde, but I guess the theme's been beaten to death.

Could not get it nice puzzle

Groby, just got over here from your link on my thread, and I have to say that I liked this problem a lot.

I solved it, but I doubt if I would have solved it if I hadn't been psychologically primed by the discussion of the Loyd.  Which brings up a whole other series of philosophical questions...oh, no !

Anyway, yours again turns on the point of black's last move. But this is neat, because you actually "tell" us was what that move was.  Also a play on ambiguities in the notational system.

Cool.

Amy

Well, the "tell" is a necessity of the puzzle interface as far as I can tell.  In order to make the solution possible I had to enter Black's last move and start the puzzle after it was done, so it appears at the bottom of the screen.

Perhaps using a FEN string instead of setting the board up by hand gets around this problem, though... I'm not sure.

I didn't know that restriction.  If I used the interface in the Loyd problem it would have given everything away. 

Although d5 attracts the solver's attention, I still like the ambiguity that it plays up.

Amy

Well it may not actually be a restriction -- a FEN string doens't contain the history, but it does contain information about castling rights and whether ep is possible.

Your puzzle most certainly would not have had the issue whether crafted by hand or via a FEN string as there are checkboxes in the interface to indicate whether castling is possible or not.  There's no equivalent in the interface for ep so I was forced to enter the move -- as I said above, I wonder if using a FEN string (which does have the ep indicator, and is accepted by the interface) might not have eliminated this.