Petrov's Defense: Three Knights Game 4.exd5 – Playing as White

The position after 4.exd5 is a small strategic victory for White. You've traded your e-pawn for Black's d-pawn, but more importantly, Black's knight on f6 is now under attack. If Black recaptures on d5, they'll allow an open centre where your better development — you already have two pieces out to Black's one — can be felt. The engine's +0.92 evaluation reflects this: you have a lasting advantage based on quicker development and central control. Your main job is not to squander that lead by rushing or making careless trades. Keep developing, keep the tension, and Black will have to solve real problems.

Stockfish's top choice for Black is Bd6, and the recommended continuation runs Bd6 Bb5+ c6 dxc6. After you check on b5, Black blocks with c6, and you capture — entering a sharp structure where Black's king is stuck in the centre and their pawn structure is fractured. This line is not the most popular at club level (it shows up in just 25,391 games), but it's the most principled. If your opponent plays Bd6, you should respond with Bb5+ immediately — don't give them time to castle or complete development for free. The check forces Black to either block or move the king, and either option helps you maintain control.

From 669,623 games in the Lichess database, here's what Black actually plays and how you score against each reply: - Nxd5 (446,605 games): White scores 53.7%. The knight recapture is by far the most common. Develop naturally — Bc4, O-O, d4 — and you'll have a comfortable game. - e4 (105,713 games): White scores 50.4% — a bit lower, but still above 50%. This push blocks the centre; you can simply take en passant with dxe6 or play d3 to open lines. - Bc5 (25,449 games), c6 (22,262 games), Bg4 (15,769 games): These are the three biggest mistakes. Each one is an inaccuracy that costs roughly 0.6 pawns compared to the best move Bd6. White scores over 54% against Bc5 and c6, and a massive 58.2% against Bg4. Knowing this, you can be alert for these subpar moves and make sure you capitalise.

The engine identifies three Black inaccuracies here, and each one gives you a chance to increase your advantage. Bc5 — This natural-looking developing move is actually a mistake. Black's bishop is better on d6 where it supports ...e4 and ...Bg4 ideas. Punish it with d4, chasing the bishop and grabbing central space. c6 — Black tries to chase your knight before recapturing, but this wastes time. Simply retreat to Nc3 or take on d5, and you'll have a lead in development that Black can't catch up from. Bg4 — Pinning the knight looks active, but it neglects the centre. Play Be2, h3, or even d4 immediately, and Black's pin will prove hollow once you develop naturally. In all three cases, keep calm, prioritise development and central control, and your +0.92 edge will only grow.