Playing White in the Queen's Gambit Declined: Queen's Knight Variation (4.Nf6)

Stockfish's top recommendation for Black here is c5, the immediate break in the centre. The follow-up runs 5.cxd5 cxd4 6.Qxd4 exd5, leading to a queen-and-pawns structure where Black has a slight initiative but no real advantage. This line is actually not the most popular choice at the board — it's been played in about 1.07 million games — and your winning chances dip slightly to 48.8% if Black knows what they're doing. Still, it's the principled test of your centre, and knowing it exists is half the battle. Against c5, you should be comfortable with the resulting open queen's pawn endgame-ish structure; don't shy away from trading queens if it simplifies to a good middlegame for you.

By far Black's most common move is Bb4, pinning your knight on c3 against the king. This has been played nearly 2.5 million times in the database, and it's good news for you: White scores 53.9% from here. The bishop on b4 does not actually threaten the knight yet, since Black's king is still in the centre and the check would be meaningless. Your typical plan is to continue development with Bd2 or a quick e3, breaking the pin and preparing to recapture on c4 with the bishop if Black ever takes. You can also consider a timely a3 to ask the bishop what it intends — it usually retreats to e7 or trades on c3, which removes your doubled-pawn worries but gives you the bishop pair. This is a solid, principled line where White's extra space and central control often tell in the middlegame.

The second-most played reply is Be7 (1.1 million games), and here your score drops to 49.0% — the only popular line where Black outperforms the average. Be7 is the classical 'Harrwitz' setup, where Black develops solidly without committing to a pin or a pawn break. You should respond naturally with e3, Bg5, or even the Bd3 + 0-0 setup. The key is not to overpress. Because your score here is slightly below 50%, the statistics suggest Black is slightly more comfortable in these slower positions. Stick to simple development: get your kingside pieces out, castle, and only then decide whether to play the minority attack on the queenside or expand in the centre with e4. Patience beats force in this line.

Two less common moves, Nc6 (470,000 games) and dxc4 (368,000 games), both score surprisingly well for you: 55.6% and 55.4% respectively. That's a full 3-4% above your baseline. Against Nc6, Black develops the knight to a natural square but blocks their own c-pawn, making it harder to challenge your centre. Your best reply is simply to carry on — maybe e3, Bd3, 0-0 — and enjoy the space advantage. Against dxc4, Black surrenders the centre and you recapture happily with e3, Bxc4, or even Qa4+ in some lines. The bottom line: don't fear these moves. They shift the game toward structures where White's central pawns and activity shine.