Indian Defense: Accelerated London System: what should White play?

In the Accelerated London System setup reached after White plays c3 and Black adopts a solid c6 and d5 barrier, White faces a choice of quiet development or subtle flank expansion. With 347,667 games recorded at this juncture, the engine designates Nd2 as the top evaluation at +0.21, closely followed by standard developmental continuations such as e3 and the prophylactic wing thrust a4. White's fundamental goal is to complete minor-piece development while securing queenside harmony against Black's potential counter-play.

Flexible Piece Development with Nd2

Developing the queen's knight via Nd2 preserves maximum flexibility, earning an engine evaluation of +0.21. In the illustrative continuation Nd2 Bf5 Qb3 Qc8 e3 e6, White immediately pressures the vulnerable b7 square, obliging Black to defend with the queen. This deployment leaves the c1-h6 diagonal open for the dark-squared bishop while delaying the commitment of the king's knight, enabling White to adapt to Black's central setups.

Solidifying the Center with e3

The traditional continuation e3 is evaluated at +0.15 and cements White's control over d4. This move supports the f4 bishop and prepares development for the king's bishop along the f1-a6 diagonal. An illustrative engine line runs e3 Bf5 Qb3 Qb6 Nd2 Nbd7, transposing into symmetrical piece placement where White retains a slight developmental edge and harmonious piece coordination.

Flank and Prophylactic Alternatives

Alternative approaches focus on controlling space before committing central pieces. The engine assesses a4 at +0.00, demonstrating a queenside clamp in a4 Bf5 Nf3 Nbd7 a5 e6. Prophylactic ideas also include h3 (+0.13), which prepares h3 Bf5 Qb3 Qb6 g4 Bg6 to secure an escape square for the dark-squared bishop, alongside classical development with Nf3 (+0.11).