Petrov's Defense: what should White play?

In this tabiya of Petrov's Defense, White has castled and must choose how to develop the remaining pieces against Black's symmetric setup. The engine marginally prefers activating the rook with Re1 (evaluating at +0.17) or immediately challenging the knight on c6 with Bb5 (+0.14), while the natural developing move Nc3 remains the most frequent practical choice.

Central Pressure with Re1 and Bb5

Both top engine choices focus on exerting indirect pressure against the e5 pawn. The move Re1 appears in 23.7% of games (13K recorded) with White scoring 49.0%, often leading to classical maneuvering via Re1 Be7 Bb5 O-O c3 a6. Direct repositioning via Bb5 is chosen in 12.8% of games (6.9K recorded) and yields a 47.3% score for White. This immediately pins the knight, threatening to compromise Black's queenside structure as seen in the continuation Bb5 Be7 Re1 O-O c3 a6.

The Popular Nc3 and Pawn Moves

The single most common path is Nc3, played in 43.2% of games (23K recorded) with an evaluation of +0.05 and a 46.5% score for White. Rather than maintaining a rigid symmetrical structure, play often sharpens along lines such as Nc3 g6 Bb5 Bg7 d4 exd4. White also frequently opts for c3, which accounts for 20.2% of games (11K recorded) and achieves White's highest score among the main candidates at 50.6%, despite an engine evaluation of -0.02. This setup prepares central support against Black's counterplay in lines like c3 d5 Bb5 Bg4 d3 dxe4. Additionally, the quiet engine alternative a4 evaluates at +0.00, demonstrated in the variation a4 Be7 Re1 g5 Nxg5 Rg8.