Ruy Lopez: Bird Variation, Paulsen Variation

The Ruy Lopez: Bird Variation, Paulsen Variation is a chess opening classified under ECO code C61 in the Open Games & French Defense family, beginning with 1.e4 e5 or 1.e4 e6, including the Italian Game, Ruy Lopez, and French Defense. It is reached after 5 moves: 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nd4 4. Nxd4 exd4 5. O-O Ne7. The resulting position leaves white to move.