Beat The ... Petrov

IN this series I am looking at the statistically best way to play against popular opening lines.

The numbers are drawn from the 2021 edition of ChessBase's Mega database, ignoring, where possible, those results that include very few games and so are statistically insignificant.

The Petrov 1.e4 e5 2.Nf3 Nf6 has largely fallen out of favour as a drawing weapon at the top level, replaced by the Berlin Variation of the Spanish.

But it retains its popularity at club level, where it is played for a win rather than mainly hoping to split a point.

White's commonest continuation is 3.Nxe5, but its excellent score of 59% is eclipsed by the 62% of 3.d4.

Position after 3.d4

Black has two major replies.

A) 3...Nxe4 (8,322 games)

White scores 61% with 4.Bd3, rising to 63% after 4...d5 5.dxe5!? (6.Nxe5 is much more popular but 'only' scores 62%).

Here the line splits.

A1 5...Nc5

White has three reasonably popular responses, the most successful being the least popular - by a small margin - 6.Nc3.

Black usually plays 6...c6, as the second-most common continuation, 6....Nxd3+ 7.Qxd3 c6 8.Bg5, wins the bishop-pair but leaves White with a huge lead in development and scoring 67%.

After 6...c6, the number of games is not statistically significant, but White scores best, 63%, with the restricting 7.h3.

A2 5...Be7

White scores 69% with 6.0-0, rising to 76% after 6...0-0 7.c4 and 6...Nc6 7.Nc3, but falling, albeit marginally, to 68% after 6...Nc5 7.Be2.

A3 5...Nc6

White scores 58% with 6.0-0, rising to 66% after 6...Bg4 7.Nc3, 76% after 6...Be7 7.Nc3 and 60%, albeit from a small sample, after 6...Bc5 7.Nc3.

B) 3...exd4 (2,338 games)

White scores 68% with the main continuation, 4.e5.

Here the line splits.

B1 4...Nxe4 5.Qxd4 d5 6.exd6 Nxd6, when White scores 68% with 7.Nc3 Nc6 8.Qf4.

B2 4...Nd5 5.Qxd4 Nb6 6.Nc3 Nc6 7.Qe4 scores an amazing 82% for White.

B3 4...Qe7 5.Be2 also scores 82% for White.