OK, so I mentioned in my previous Mate in 2 ( http://www.chess.com/forum/view/more-puzzles/mate-in-2---trickier-than-it-looks ) that there was a puzzle next to it in the book which also had my son and I thinking for a while. Well here it is...

Nice one. Thx. (I actually got this one. :)

Nice one.

My first guess was to move the king to b8. But it would require more moves and possibly white loses.

I found this one to be more difficult!  I think I have trouble spotting strong retreating moves.

@Frezco: You've been a member since 2009 and never played. Don't you like chess?

@ Marc_Turner: Love it, especially 960 and related ideas, but my plate's full (family stuff and my website).  I'm no good at blitz, and I can't commit myself to timed games on line.  I play some vote chess and some over the board.