Find the decisive blow (difficulty 855)

12345678 hgfedcba

Black to move

Show solution
12345678 hgfedcba
  1. g3–e1 key move
  2. g1–h2
  3. f5–h5

What makes it

The bishop sets up a forced mate in two. A piece slips off the line and the attack opens up behind it. Difficulty 855: an approachable find.