Petrov's Defense Trap #1 (Pinning the Knight)

Today, I will be posting an article on a simple trap in the Petrov's Defense that catches many beginners. The line goes: 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. Qe2. This is known as the Cozio Attack of the classical varation of the Petrov. The Queen attacks and pins the black knight on e4. The best move is 5. ... Qe7, unpinning and defending. However, many beginners will play 5. ...d5 or 5. ...f5, defending the knight. However, this is pet with 6. d3, attacking the knight. The knight can not move because it is pinned and white wins a piece for a pawn after black defends with 6. ...Qe7. This can also happen with black. Here is the trap: