Black answers 2.Nf3 not by defending the e5-pawn but by attacking the white one. After 1. e4 e5 2. Nf3 Nf6, the Petrov’s Defense begins with a counterattack that refuses the slow strategic argument of the Ruy Lopez and the Italian. Both sides have placed a knight on f3/f6, both sides have a pawn on the fourth rank, and the rest of the game is about who can resolve the symmetry on favourable terms.
Also known as the Russian Game in honour of Alexander Petrov, the nineteenth-century Russian theorist who studied the defence systematically, the opening belongs to ECO C42 at its entrance and includes the Classical Attack, the Cochrane Gambit, the Cozio Attack, the Damiano Variation, and a handful of less common branches. Its reputation has changed several times in the past century, but its essential argument has not: that Black does not need to defend the e-pawn to keep equality.
Origins
Alexander Petrov was a Russian master and theorist who published a chess manual in 1824. The defence that bears his name was already known — Greco had played similar positions two centuries earlier — but Petrov’s analysis gave the line a coherent treatment. He showed that after 3.Nxe5 d6 4.Nf3 Nxe4, the resulting symmetry does not favour White, and that with accurate play Black achieves equality.
For most of the nineteenth century the Petrov was treated as a sound but unambitious defence. Players who wanted to win with Black preferred more imbalanced openings. The Petrov’s reputation as a drawing weapon dates from this period and has never entirely faded. In the early twentieth century, however, the defence acquired a more serious theoretical standing. Capablanca and Alekhine both used it, and Lasker studied its endings carefully.
The opening’s modern career has been shaped by elite players who used it as a primary defence against 1.e4. Anatoly Karpov used the Petrov occasionally; Vladimir Kramnik adopted it as a primary weapon during his world-championship career; and Fabiano Caruana made the defence part of his repertoire in the 2010s, including in his 2018 world-championship match against Magnus Carlsen in London. In that match the Petrov was used in several decisive games and helped Caruana hold the classical portion of the match to a 6–6 tie.
The symmetrical reply
The Petrov’s distinguishing feature is symmetry. After 1.e4 e5 2.Nf3 Nf6, both sides have made the same two moves. The most natural continuation is 3.Nxe5, attacking the now-undefended e5 pawn while pinning the f6-knight to the e4-pawn’s threat. Black’s accurate reply is not 3…Nxe4 immediately — that is the Damiano Variation, in which White wins a pawn after 4.Qe2 with threats against the knight on e4.
The correct sequence is 3.Nxe5 d6, attacking the knight and forcing it to retreat. After 4.Nf3, Black plays 4…Nxe4 and the symmetry resumes. The middlegame turns on small differences. Both sides have a knight on the fourth rank; both have a pawn on the second rank where it started; both will develop their pieces in similar ways. White’s advantage is the first move, which translates into the right to choose the structural commitments first.
Black’s strategic plan in the main lines is to complete development with …Nf6 (after the knight is challenged), …Be7 or …Bd6, …O-O, and a careful approach to the c6/c5 break. The position is not lifeless. The half-open e-file and the slight asymmetry that any move creates give both sides chances to play for a win.
Main lines and gambits
The Classical Attack, the modern main line, runs 3.Nxe5 d6 4.Nf3 Nxe4 5.d4 d5 6.Bd3 Nc6 7.O-O. White develops cleanly and waits for Black to commit to a piece arrangement. Black’s typical setup is …Be7 or …Bd6, …O-O, and a careful prophylaxis against White’s break c4. The position is balanced but requires precision. Caruana–Carlsen from the 2018 world-championship match in London is the canonical modern reference for this structure.
The Cochrane Gambit, 3.Nxe5 d6 4.Nxf7, is a more aggressive nineteenth-century idea. White sacrifices the knight for a pawn and the chance to expose the black king. At master level the gambit is unsound, but it is still seen in club play and online blitz, and it has been used by elite players including Veselin Topalov as a surprise weapon. The line is theoretically inferior but practically dangerous, particularly against unprepared opposition.
The Cozio Attack, with 3.Nc3, declines the immediate exchange and develops a piece. Black usually replies 3…Nc6, transposing to the Four Knights Game. This is not really a Petrov in the strict sense — the symmetry of the original move has been abandoned — but it is included in the C42 family because it begins with the same first three half-moves.
Historical context
The Petrov’s reputation has always suffered from its association with drawn games. At master level the defence has historically scored close to evenly, and many of its main lines do lead to balanced endings. This is not, however, the same as saying the opening is sterile. The 2018 world-championship match showed that the Petrov, played accurately, can hold even the most demanding opponent to small disadvantages — and that those small disadvantages can sometimes be converted into wins by either side.
The line’s modern champion has been Caruana, who used it consistently in his world-championship cycle. Kramnik used it earlier as a way to neutralise 1.e4. Hikaru Nakamura has used it occasionally. At the engine level, the Petrov is treated as the most solid defence to 1.e4 at the elite level — the line that gives White the smallest advantage in absolute terms while requiring Black to play with significant accuracy in return.
How to study it
For Black, the first step is to learn the structural target — the position after 3.Nxe5 d6 4.Nf3 Nxe4 5.d4 d5 6.Bd3 Nc6 7.O-O Be7. This is the position from which most modern Petrov middlegames begin, and understanding it makes the move-order details less important. Pay particular attention to White’s break c4 and Black’s responses with …c6, …dxc4, or …Nf6 depending on circumstances.
Against the Cochrane Gambit, learn the defensive sequence with …Kxf7 and central consolidation. The king is exposed, but Black has an extra piece, and the line is theoretically resolved.
Against the Cozio with 3.Nc3, study the Four Knights Game as a separate opening. The transposition is so common that treating the Petrov as the original Russian Game and the Four Knights as a related but distinct opening is the standard practical approach.
For White, the choice is between accepting the strategic challenge of the Classical Attack and choosing one of the sharper sidelines. The Classical Attack is the most ambitious and requires the most preparation; the Cozio is simpler but offers less of an advantage; the Cochrane Gambit is a practical weapon at sub-elite levels but objectively unsound.
Model games for either side should include Caruana’s recent Petrov practice — particularly his games against Carlsen in 2018, including the eleven classical games of the match — and Kramnik’s earlier work. The Petrov is one of the few openings where a small number of high-level games gives a complete understanding of the modern theoretical state.
— Editor’s desk, 23 May 2026