Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Bc5/4. c3/4...Nf6/5. d4

= Center Attack =

5. d4
White attacks the center with 5. d4, attempting to create a strong pawn center with the d4 and e4 pawns. Black has to respond with exd4, or else surrender the entire center to White.

Theory table
'''1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d4'''