Find the decisive blow (difficulty 975)

12345678 hgfedcba

Black to move

Show solution
12345678 hgfedcba
  1. h3–f3 key move
  2. e2–f3
  3. g2–f3

What makes it

The win is mate in two, paid for with a 4-point sacrifice. The shot starts with the rook. Difficulty 975: an approachable find.