Chess puzzle

A game ends with the move
6.gxf8=N mate. How did it go?

NB please don't post the solution if you have seen it somewhere else

Nice one. I had to get past the stage where I thought it is not possible. I leave the solution unposted for others to find it.

Originally posted by Quirine
A game ends with the move
6.gxf8=N mate. How did it go?

NB please don't post the solution if you have seen it somewhere else

I've seen this one a few times, but I always forget the solution and have to re-solve it. But I think I'm getting faster each time... 😲 This time took about 10 minutes without a board.