Suffolk Chess

At first glance it just doesn't seem possible.   In this position it's White to play and win.   OK, White has a pawn about to promote, but threats of Nf7+ appear to prevent this.   On the other hand, Black is poised to promote the c and e pawns, as well as holding a considerable material advantage.

If you haven't seen this puzzle before, have a go at solving it.   There's not much use in using a computer - there's no way it'll see far enough ahead from this position.   The main line, which leads to mate, is 12 moves long!


Answers to please!