Queen's Gambit Declined - Ragozin variation
1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Nf3 Bb4
White plays the queen's pawn to d4. Black pushes the queen's pawn to d5. White moves the c-pawn to c4.
Black plays the king's pawn to e6. White develops the knight to c3. Black develops the knight to f6.
White moves the knight to f3. Black develops the dark-squared bishop to b4.