French Defense: Winawer Variation, Retreat Variation

The French Defense: Winawer Variation, Retreat Variation is a chess opening classified under ECO code C17 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 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. a3 Ba5. The resulting position leaves white to move.