Find the decisive blow (difficulty 1560)

12345678 hgfedcba

Black to move

Show solution
12345678 hgfedcba
  1. f8–h8 key move
  2. f3–g4
  3. h2–g2

What makes it

1 points of material given up forces mate in ten. The blow comes from a discovered attack — one piece moves, another fires. 19 half-moves of forced play.