Answer
47. Nf6+!!
It's checkmate in 2 in one of two ways.
47...Qxf6
48. Qg4#
47...Kh4
48. Qh3#
https://www.chess.com/analysis/game/live/97535431411?tab=analysis
It's a speed chess game I just watched. Let me know if I screwed this up. I can't copy and paste from the site.
I was so fixated on how black was going to win - I didn't see the danger at all. I only knew black was toast due to the evaluation bar suddenly indicating mate in 2.
[Edit - I fixed a mistake]
Not op, but your original notation is for pawns.
Fuck, pawns have a special notation that only they use? I thought I could just name the starting square and the square it finishes on and people would understand? How else am I supposed to answer without learning a special language?
You name the piece and the square it moves to, you don't name the origin square, that's implied by the piece (unless there are multiple of the same piece that can move to the same square which you would then denote which rank or file differentiates the pieces)
Pawns do not have a symbol so if you were to say g6 you are saying a pawn is moving to g6.
N = knight
B = Bishop
R = rook
Q = Queen
K = King
To indicate a capture, use an x. So NxG6 means knight moves and captures whatever is on g6.
To indicate check, use a +. So NG6+ in this case.
To indicate mate, #. Ng6+, QxG6, Qg4#.
Sorry for being a nerd