Play the Philidor Defense: Exchange Variation with 4.Nxd4

You've played ...Nf6, developing a piece and pressuring the e4 pawn. Your core task is to complete development while keeping the position solid. White's best move here is Nc3, defending e4 and developing naturally. That continuation leads to a typical Italian-style setup where White is slightly more comfortable — but Black is not under direct attack. Your goals include getting your light-squared bishop to e7 or d6, castling kingside, and challenging the centre with ...c5 or ...d5 when the time is right. The engine's best line runs Nc3 Be7 Bf4 O-O, and from there you'll aim to finish development before choosing a central break.

Over 3,108,961 games have reached this exact position on Lichess, giving us a rich dataset. White wins 50.1%, draws 4.2%, and Black wins 45.7% — so while the engine calls this clearly favourable for White, practical results are closer than you might expect. The most-played move, Nc3 (2,204,451 games), scores 51.5% for White. That's solid but not crushing. More interesting: several of White's other options actually score worse for them. Bd3 scores 49.1% for White, Bg5 scores 45.9%, and both f3 and Qf3 score only 45.9% and 45.7% respectively. That means many White players leave the best path, and you can capitalise.

The engine identifies three moves White might play that are genuine inaccuracies: Bg5, f3, and Qf3. Each one gives you a chance to improve your position significantly. If White plays Bg5 (losing roughly 0.8 pawns of advantage), you can ask yourself what that bishop is doing — it pins the knight but leaves White's development slightly awkward. The move f3 (losing about 0.7 pawns) weakens the kingside and takes a square from the g1-knight. Qf3 (losing around 0.6 pawns) develops the queen early, which can become a target. When you face these moves in the drill, look for active replies that exploit White's misplaced pieces or lost tempo.

Nc3 is by far the most frequent move your opponent will try — over 2,204,451 games in the dataset. After Nc3, the engine continues Be7 Bf4 O-O, which is a natural developing sequence. Your bishop goes to e7 (safe and solid), then you castle. From that setup, typical plans include playing ...c5 to challenge the knight on d4, or ...d5 to attack the centre when the timing is right. Keep an eye on the f4-bishop — it eyes your kingside, so be cautious about pushing ...g6 or ...h6 without a specific reason. The key is steady development: don't rush, don't weaken your structure, and wait for White to commit before choosing your counterplay.