Diagram above: Black to Play. What would you do?
Scroll down to see the solution.
Naturally, once we observe that the pawn on f2 is pinned, we see that black can simply capture the white queen, 1… Qxg3.
Diagram above: 1… Qxg3 wins the white queen because the pawn on f2 is pinned by the black bishop on b6.
This tactic was made possible as a consequence of white’s last move, 1.0-0. White effectively pinned their own pawn on f2–which meant the white queen on g3 became undefended.
The type of pin in this tactic is also referred to as an “absolute pin” since the f2-pawn is pinned to the king–which implies the pinned piece/pawn cannot move since it will expose the king to check.
Note: In the above comments I linked “pinned” and “absolute pin” to respective pages with more information on the term. In other exercises, where applicable, I will add such relevant links to the comments too.