Ruy Lopez: Morphy Defense, Modern Steinitz Defense: what should White play?

In the Ruy Lopez: Morphy Defense, Modern Steinitz Defense, the most effective continuation for White is Bb3, which maintains the pressure on the center while preserving the light-squared bishop. This move is played in 96.0% of recorded games (420,000 instances) and carries an engine evaluation of +0.13. By retreating the bishop to the b3 square, White prepares for a central confrontation while avoiding the immediate loss of the minor piece to Black's queenside expansion.

The dominance of Bb3

The move Bb3 is the standard response in this position because the a4 is currently under attack by the pawn on b5. Retreating the bishop allows White to maintain the tension in the center and prepare for the main line Bb3 Nxd4 Nxd4 exd4 c3 dxc3. This sequence transitions the game into a structure where White seeks long-term compensation for a pawn or maintains a solid central presence. The overwhelming popularity of this move reflects its status as the only theoretically sound way to maintain an advantage.

Strategic alternatives and risks

While Bb3 is the primary choice, other moves exist but result in significant evaluation drops. The move d5 is the second most common choice, played in 3.7% of games (16,000 recorded), but it leads to an engine evaluation of -0.64. In this line, d5 bxa4 dxc6 Ne7 c4 Nxc6, Black gains the bishop pair in exchange for a somewhat compromised pawn structure. Other attempts such as Bg5 or c4 are statistically rare, appearing in fewer than 300 games combined, and are considered tactical errors with evaluations below -3.18.

Consequences of the bishop sacrifice

The move Bxb5 is a speculative sacrifice that has been attempted in only 76 recorded games. The engine evaluates this position at -3.82, suggesting that White does not receive sufficient compensation for the piece. Following the line Bxb5 axb5 Nc3 b4 Nd5 Nf6, Black successfully consolidates the extra material while White's initiative stalls. Consequently, maintaining the bishop via the b3 square remains the only recommended path for White to contest for an opening advantage.