Chessy
Petrov's Defense: Three Knights Game – Playing White After 3...c6
After 1.e4 e5 2.Nf3 Nf6 3.Nc3 c6, Black tries to avoid the main lines of the Petrov by shoring up the centre with ...c6. That pawn move weakens the d6 square, and you can immediately punish it: 4.Nxe5! wins a pawn because 4...Nxe4?? loses to 5.Qe2. The resulting position is already promising for you. Stockfish rates it +0.73, a clear edge for White. That means you are firmly better here — now you just need to know how to follow up. Jump into the drill below and practise converting this advantage against the engine.
Play the Petrov's Defense: Three Knights Game: c6 against the engine
Free, no signup — you play white, the engine adapts to your level.
Ready to practise converting this advantage? Play through the position against the engine in the drill below — it adapts to your moves and helps you learn the 4
Create a free account →What You're Fighting For
Black's third move, 3...c6, supports a future ...d5 but does nothing to develop or challenge your centre. By capturing on e5 you immediately win a pawn while Black's knight remains on f6, unable to recapture. The engine's top choice for Black is 4...Qe7, which attacks the knight and forces it back. After 5.d4 d6 6.Nf3, you've built a strong pawn centre with a lead in development. Black's queen on e7 is a bit awkward — it blocks the bishop and can become a target. Your advantage is structural and developmental; you want to keep the centre solid, complete your development with Be3 and Bd3, and castle quickly. Black's main counterplay will involve ...d5 or ...Bg4, but with accurate play you should convert your extra pawn into a full point.
The Statistics Tell a Clear Story
Over 128,468 games from this exact position, White scores an impressive 56.5% with only 3.5% of games ending in draws. Black wins 40.1% — a significant gap. The statistics also reveal which replies give you the best results. When Black plays 4...d6 (18,281 games), your win rate jumps to 61.2%. The rare 4...Bd6 (9,295 games) is even better for you at 62.1%. The most popular move, 4...d5 (36,616 games), sees you scoring 55.9% — still excellent. Only one Black reply gives you pause: 4...Bb4 drops your score to 49.8%, which hints that Black's best practical chance is to pin your knight on c3 immediately.
Punish Black's Most Common Mistakes
Three of Black's natural-looking replies are actually inaccuracies that make your life even easier. Here they are, ranked by how much they cost Black: - 4...d6 – an inaccuracy that loses roughly 0.9 pawns. Black unnecessarily defends the pawn that's already gone, wasting a tempo. The engine says 4...Qe7 was better. - 4...Bb4 – an inaccuracy that loses roughly 0.8 pawns. Pinning the knight on c3 looks active, but Black hasn't solved the problem of the missing e-pawn. - 4...d5 – an inaccuracy that loses roughly 0.6 pawns. The most popular move is still inaccurate! Black tries to counter-attack immediately, but your extra pawn and strong centre should prevail. The only accurate move is 4...Qe7, which the engine recommends. If your opponent plays anything else, you can be confident you've already gained an edge.
How to Handle the Engine's Best Reply: 4...Qe7
When Black plays the engine-recommended 4...Qe7 (attacking your knight), you should retreat with 5.d4! This is stronger than moving the knight immediately because it grabs space in the centre first. After 5...d6 (Black attacks the knight again), simply play 6.Nf3. You've kept the extra pawn, built a d4-e4 pawn duo, and all your pieces remain flexible. Black's queen on e7 blocks the f8-bishop — a small but real inconvenience for them. From here, develop naturally: Bd3, 0-0, Re1, and Be3 are all good moves. Watch for ...Bg4 pinning your knight on f3; if that happens, Be2 or h3 are sensible. Your plan is simple: complete development, keep the centre, and enjoy your material advantage.
Results across 128,468 Lichess games
| Most-played continuation | Games | White wins |
|---|---|---|
| d5 | 36,616 | 55.9% |
| Qe7 | 20,745 | 54.7% |
| d6 | 18,281 | 61.2% |
| Bb4 | 15,235 | 49.8% |
| Bc5 | 14,188 | 55.1% |
| Bd6 | 9,295 | 62.1% |
Frequently asked questions
Is 4.Nxe5 actually winning a pawn in the Petrov Three Knights with ...c6?
Yes, absolutely. After 3...c6, the pawn on e5 is undefended — the knight on f6 does not protect it. So 4.Nxe5 simply wins a pawn. If Black tries 4...Nxe4, you reply 5.Qe2 forking the knight on e4 and the king on e8, winning a piece. That's why 4...Qe7 is Black's only accurate reply.
Why is 4...d5 the most popular move if it's an inaccuracy?
Many club players instinctively push ...d5 to challenge the centre, but in this position it's a mistake. The move 4...d5 loses roughly 0.6 pawns compared to the engine's suggestion of 4...Qe7. It's popular because it looks natural — Black attacks your e4-pawn and gains space — but you already have an extra pawn, and 4...d5 does nothing to address that.
What should I do if Black plays 4...Bb4?
Black pins your knight on c3, threatening to win it if you don't react. The simplest answer is 5.d4, the same idea as against 4...Qe7. If 5...Nxe4??, then 6.Qe2! attacks the knight and threatens Qxe4+ winning the bishop on b4. More likely Black will play 5...d6, and after 6.Nf3 you're up a pawn with a strong centre. The statistics show 4...Bb4 is your toughest reply (49.8% White wins), but you're still slightly better.
What's the typical middlegame like in this line?
You'll have an extra pawn and a healthy pawn centre with d4 and e4. Black often tries to generate activity with ...Bg4 pinning your knight on f3, or ...0-0 followed by ...Re8 and ...d5 breaks. Your job is to develop calmly (Bd3, 0-0, Re1, Be3), keep the centre solid, and exchange pieces when it simplifies into a winning endgame. The engine's +0.73 evaluation reflects that with normal play your extra pawn should be the deciding factor.
How many games feature the Petrov's Defense: Three Knights Game: c6?
Over 128K Lichess games have reached the Petrov's Defense: Three Knights Game: c6 position. White wins 56.5%, Black wins 40.1%, with 3.5% draws — based on real rated games.