Ruy Lopez: Morphy Defense, Alapin's Defense Deferred: what should White play?

In the Ruy Lopez: Morphy Defense, Alapin's Defense Deferred (ECO C70), White's most accurate theoretical choice is O-O, securing king safety while maintaining an engine evaluation of +0.92. White also frequently chooses c3, which prepares central expansion and appears in 60.7% of the 24,792 games recorded in the database. Both moves offer White a reliable initiative against Black's active dark-squared bishop on b4.

Strategic Priorities: Castling vs. Central Preparation

Although O-O is the engine's top choice, c3 is the most heavily played continuation with 15K recorded games and a White scoring rate of 65.1%. Opting for c3 challenges Black's piece coordination immediately by preparing a classical pawn push toward d4. Choosing O-O instead—selected in 28.1% of games (7.0K recorded)—prioritizes rapid development and scores 64.3% for White.

Engine Continuation in the Main Line

Following the top-ranked O-O, the engine highlights the continuation O-O Nf6 Bxc6 bxc6 Nxe5 O-O. In this line, White exchanges on c6 and captures on e5 before Black completes kingside castling. If White instead selects c3 (evaluated at +0.87), play often transitions via c3 Ba5 O-O d6 d4 b5, where Black retreats the bishop to a5 and gains queenside space while White establishes the center.

Alternative Options for White

Aside from the primary continuations, White can challenge the black bishop immediately with a3, which occurs in 9.5% of games (2.3K recorded) with an evaluation of +0.48. In the illustrative line a3 Ba5 Bxc6 dxc6 O-O Qd6, White scores 63.3%. Rarer choices include the preventive retreat Bb3 (played in 1.7% of games, evaluated at +0.28) and h3 (seen in just 18 recorded games, evaluated at +0.43).