Four Knights Game: Spanish Variation, Rubinstein Variation, Marshall Gambit

The Four Knights Game: Spanish Variation, Rubinstein Variation, Marshall Gambit is a chess opening classified under ECO code C48 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 6 moves: 1. e4 e5 2. Nf3 Nc6 3. Nc3 Nf6 4. Bb5 Nd4 5. Ba4 Bc5 6. Nxe5 O-O. The resulting position leaves white to move.