Caro–Kann Defence
A pinned pawn cannot save the king
The attacking idea
Use a knight check. The e-pawn is pinned and cannot capture the knight.
The temptation
A natural move overlooks that the e-pawn is the king's only shield on the open file.
If they defend
Exchange the attacking knight before it can jump in with check.
Look for the tactic as you develop. The opponent can choose a different route.
They take the bait
1. e4 1… c6 2. d4 2… d5 3. Nc3 3… dxe4 4. Nxe4 4… Nd7 5. Qe2 5… Ngf6 6. Nd6#
They defend
1. e4 1… c6 2. d4 2… d5 3. Nc3 3… dxe4 4. Nxe4 4… Nd7 5. Qe2 5… Ndf6 6. Nxf6+ 6… Nxf6 7. Nf3