Queen's Pawn Game: London System: what should White play?

In the Queen's Pawn Game: London System, the position after Black develops the bishop to g4 presents White with several sound developmental setups, most prominently Nc3 and a3. While the engine narrowly favors the classical knight deployment Nc3 with an evaluation of +0.33, the prophylactic a3 also offers an evaluation of +0.31, preventing queenside piece incursions. Across 136,428 recorded games, these continuations allow White to maintain a comfortable central presence.

The Strategic Value of Nc3 and a3

The most popular option in the database is Nc3, played in 56.0% of games (76K recorded) with White scoring 56.6%. It actively develops a minor piece and pressures the center, commonly leading to the illustrative continuation Nc3 Bb4 Rc1 O-O Be2 dxc4. Alternatively, the quieter pawn advance a3 appears in 8.7% of games (12K recorded) and secures a 55.0% score for White. In the engine main line a3 dxc4 Bxc4 e5 Bxe5 Nxe5, White secures central activity while keeping the b4 square defended against enemy minor pieces.

Space-Gaining and Developing Alternatives

White can also resolve central tension on the queenside immediately by selecting c5, chosen in 14.5% of encounters (20K recorded) with an engine evaluation of +0.31. This ambitious advance scores 63.8% for White, often triggering the illustrative response c5 Nh5 Nbd2 Nxf4 exf4 a6. Other steady options include Nbd2, played in 10.5% of games (14K recorded) with an evaluation of +0.26 and a 52.8% score, and Be2, seen in 10.3% of games (14K recorded) evaluated at +0.21. These setups prioritize harmonious piece coordination while naturally preparing kingside castling.