London System: what should Black play?

In the London System (ECO A48), the standard and most effective continuation for Black is Bg7. Chosen in 87.5% of recorded games (6.09M recorded), it immediately completes the kingside fianchetto, preparing castling while exerting long-range pressure across the long diagonal. The move holds an engine evaluation of +0.09, leaving White with a 49.9% scoring rate.

Strategic ideas behind the main line

By playing Bg7, Black follows classical Kings Indian and Grünfeld setups against White's solid piece arrangement. An illustrative engine continuation develops via Bg7 e3 d6 c3 Nh5 Bg5, where Black prepares central resistance and targets White's active dark-squared bishop. This approach allows Black to maintain piece harmony and retain flexibility regarding future central pawn breaks.

Classical alternatives with central pawns

Players seeking different pawn structures sometimes opt for immediate pawn commitments. The strike d5 appears in 4.2% of games (295K recorded) with an evaluation of +0.20, leading into lines like d5 h3 c5 e3 Bg7 c3 where White scores 51.5%. Alternatively, d6 represents 7.7% of games (539K recorded) with an engine evaluation of +0.31, leading to continuations such as d6 Nc3 Bg7 e4 O-O Qd2. Both alternatives transition toward recognized defensive frameworks, although they yield marginally higher engine evaluations for White than the primary move.

Minor sidelines and immediate piece challenges

Other options are observed far less frequently in practice. An immediate hunt of the bishop with Nh5 is seen in 0.3% of games (18K recorded, evaluated at +0.31), which can prompt Nh5 Bd2 Bg7 e4 c5 Bc3. Similarly, the modest pawn move c6 accounts for 0.2% of games (16K recorded) with an evaluation of +0.35, where the engine highlights c6 h3 Bg7 e3 Qb6 Qc1. Neither sideline challenges the supremacy of the standard kingside development.