Chess in 40 SecondsFrom's Gambit
Black to move. Mate in 1.
Snort took your queen on g3. The road to his king is open. Mate him.
Hint
The long diagonal to his king is wide open.
Answer
Bxg3# — Checkmate! You gave the queen to open one diagonal.
The idea
Giving your queen to open one long diagonal is worth it when it ends in mate.
This chess trap is one of 30 quick puzzles in the Chess in 40 Seconds trainer: find the move on the board, get a hint if you're stuck, and learn the idea so you never fall for it in your own games.