Chess Online

It's obvious that White can't advance the king or promote the pawn (1. b5 Kb6), so mate on the back rank with the pawn on b6 looked most likely. I figured that this meant two pawn moves and one queen move between moves 1 and 3. However, going through queen moves to corral the king in this way convinced me that none of them worked, so I moved on to and eliminated two very unpromising ideas: (1) Mating on the a-file (would have made more sense if the pawn were on the c-file); (2) 1. Kb3 aiming at c4 (much too slow).

I then went back to pawn pushing idea and noticed the mating pattern and spent a long time failing to find an way to reach the position after 1. b5 Kb6 2. Kb4 Ka7 but with Black to move.

Now very frustrated, I essentially restarted from the beginning and came to the same conclusions, but I finally noticed 1. Kb3 could set up the above mating pattern, just one rank down the board.

Had to think about it before backing up!

The puzzle is based on avoiding stalemate! You have to back up!