Petrov’s Defence
A discovered check wins the queen
The attacking idea
Open the e-file with check while the knight attacks d8. The king must be saved first.
The temptation
Moving the knight back looks safe but opens a checking line against the king.
If they defend
Play d6 before recovering e4. This avoids copying White's capture too soon.
Look for the tactic as you develop. The opponent can choose a different route.
They take the bait
1. e4 1… e5 2. Nf3 2… Nf6 3. Nxe5 3… Nxe4 4. Qe2 4… Nf6 5. Nc6+ 5… Be7 6. Nxd8 6… Kxd8
They defend
1. e4 1… e5 2. Nf3 2… Nf6 3. Nxe5 3… d6 4. Nf3 4… Nxe4 5. d4 5… d5 6. Bd3