Forced positioning by check.
2)kf1 f3
The King moves into "Opposition."Black's move is "Forced" as 2)... h2 allows 3)nf2 and white mates, proof that the "King and Knight can Mate".
3)kf2 h2
King moves into "knight's Jump Opposition" "Black's move is his "Only Move"
4)kf1 f2
Back into "opposition" goes White. Black's move again is his "Only Move"
5)nf2 mate
