Rat Defense: Small Center Defense: what should White play?

In the Rat Defense: Small Center Defense (ECO C00), White holds a commanding space advantage with pawns already established on d4 and e4. The primary recommendation for White is Nf3, which develops a kingside minor piece toward the center while defending the central pawn structure and preparing kingside castling. Across nearly eight million recorded games in this position (7,928,365 games), this straightforward classical development secures an engine evaluation of +0.75.

Natural Development with Nf3 and Bd3

White's most prominent plans revolve around natural piece placement to support the full pawn center. Alongside Nf3, the engine ranks Bd3 as an equally potent continuation with an evaluation of +0.76. Both setups prioritize rapid kingside mobilization before deciding on the ultimate placement of the queenside pieces. As demonstrated in the engine variation Bd3 Nf6 Nf3 Nbd7 c4 g6, White can smoothly transition into a broad pawn chain with a subsequent expansion via the c-pawn.

Alternative Setups for White

White also possesses flexible alternatives that control central squares from different angles. The move Nc3 scores an evaluation of +0.70, where play can continue with active piece pressure as seen in Nc3 Nf6 Be3 Be7 Qf3 e5. Other viable options include the prophylactic a3 and the direct development Be3, both evaluated at +0.67. While Black adopts a hypermodern, restrained posture behind pawns on d6 and e6, White retains a clear spatial plus regardless of which classical developing scheme is selected.