Scandinavian - Kiel variation
1. e4 d5 2. exd5 Nf6 3. d4 Nxd5 4. c4 Nb4
White plays the king's pawn to e4. Black plays the queen's pawn to d5. White captures on d5 with the king's pawn.
Black develops the knight to f6. White moves the queen's pawn to d4. Black captures with the knight on d5.
White plays the c-pawn to c4. Black jumps the knight to b4.