Indian Defense: London System: what should White play?

In the Indian Defense: London System, White faces an immediate check from Black's dark-squared bishop on the b4 square. The standard choice for White is c3, which solidifies the center, neutralizes the check, and blunts the bishop while maintaining an engine evaluation of +0.45. Another fully viable path is Nbd2, developing a minor piece to resolve the check while preserving flexible central pawn options.

The Mainline Choice: c3

The move c3 dominates the database, appearing in 88.9% of recorded games (172K recorded) and earning White a 57.1% scoring rate. By bolstering the d4 pawn, White constructs the signature London System pyramid structure and prompts the opposing bishop to reconsider its outpost. A common continuation following this approach runs c3 Be7 h4 c5 e3 Nc6, where White secures steady spatial control on the kingside and center.

Developing with Nbd2

The primary alternative Nbd2 is favored as the top engine choice with an evaluation of +0.40, scoring 55.8% across 13K games (6.6% of games). This interposition keeps the c-pawn free for future options and develops a queenside piece without disrupting White's piece coordination. An illustrative continuation is Nbd2 d5 c3 Bd6 Bg5 h6, where White transitions smoothly into standard setups while actively maneuvering around Black's central challenge.

Less Frequent Interpositions

Other ways to meet the check yield lower evaluations and score less favorably for White. Blocking the diagonal via Nc3 is chosen in 3.8% of games (7.4K recorded) but carries an evaluation of -0.38 and scores 51.1%, as it self-pins the knight in front of the c-pawn. Retreating the bishop via Bd2 scores 49.4% across 1.2K games (-0.11 evaluation), while Nfd2 is rare at 186 games, yielding an evaluation of -0.01.