Lesson
White to move. Main line: 1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nd7 5. Qe2 Ngf6 6. Nd6#
The quiet 5.Qe2! sets the trap. After the natural 5...Ngf6??, 6.Nd6# is mate: the knight checks the king on e8, which is hemmed in by its own queen (d8), bishop (f8) and pawns (e7, f7) — a smothered mate delivered straight out of the opening.
Black must play 5...Ndf6 or block the e-file first; developing the g8-knight walks into the fork of king and the e2–e8 pin. It is a perfect example of why a queen move to e2 in these lines can be far more dangerous than it looks.