Tarrasch Trap (Berlin)

Black castles one move too early and a routine-looking exchange sequence wins a clean pawn.

Ruy Lopez, Berlin Defence — Black falls in with O-O

Trap data: Wikipedia — Ruy Lopez, Tarrasch Trap (CC BY-SA 4.0); Lichess chess-openings (Ruy Lopez: Berlin Defense, Tarrasch Trap, ECO C66) (CC0-1.0).