In the third round of the recent Judd Lauger Memorial Classic in DeKalb, Illinois, my opponent and I reached the following position:
My opponent (white) played 49.Re1, and I soon won after 49…Re2 50.h5 Ng4 51.h6 Kxg3.
What crushing move should my opponent have played instead of 49.Re1 ?
Bill Smythe
Rf3. Cool!
Correct, of course. You didn’t even give jwiewel a chance to jump in here. 
It’s easy to miss this, as it appears to just fall for a back rank mate, with both possible interpositions being on undefended squares. Talk about illusory!
I noticed it while my opponent was pondering his 49th move. I had to sit there with a poker face hoping he wouldn’t see it – which, obviously, he didn’t.
Bill Smythe
It’s really cool - has the appearance of a study (although it’s too easy to be one, but you might be able to add a few complicated moves before it and make it into one).
If you had just said “what’s happening here?” one might not find that save. I asked myself that question as I found the solution (which is pretty easy with the hint, because white has so few possible ways to save him/herself). I think I probably would have found it, but the sense of dejection white was probably feeling is often a huge hindrance. I tell students to treat each position as a ‘tabula rasa’ (blank slate), but that is easier said than done.
The surprise is why White did not find Rf3. It is the only move that makes a real threat. When the King, especially in this case the Black King, has no squares to run to, the first check wins. The diagram demonstrates the use of “discovery” and “interference” tactical elements. Since it is not a check, it is a relatively quiet move that threatens to threaten. In Informant, the symbol for box would be used to show that Rf3 is forced or the only move. I have to wonder what the time situation was as in time trouble it is easier to find routine Rook moves like Re1 that attack forward than moves that contain a sideways threat. Bravo for being able to sit there nonchalantly without your head exploding while waiting for the opponent to move. Any flinch would alert him that there was something better to play.
In my playing days, this is where I would shrug, give one of those ‘roll my eyes’ looks and walk away from the board for awhile.
Really cool. Thanks for sharing, Bill, and congrats on the win (wins of lost games count).