Queen's Gambit Declined Slav - Suechting variation
1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 Qb6
White pushes the queen's pawn to d4. Black pushes the queen's pawn to d5. White pushes the c-pawn to c4.
Black pushes the c-pawn to c6. White develops the knight to f3. Black develops the knight to f6.
White jumps the knight to c3. Black moves the queen to b6.