Beat The ... Catalan

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 Catalan: 1.d4 d5 2.c4 e6 3.Nf3 Nf6 4.g3 is a slow-burn opening in which Black is not under immediate pressure, but can easily play sensible-looking developing moves without a proper plan and land in big trouble in the early middlegame.

Black's commonest reply, 4...Be7, scores just 37%, but 4...dxc4 scores an impressive 47%.

Position after 4...dxc4

White has two main continuations.

A) 5.Bg2 (10,245 games)

Black has several popular responses, but best statistically is 5...a6, which scores 49%, after which the line splits.

A1 6.0-0 Nc6, after which the line splits again.

A1.1 7.e3 Rb8, with another split: A1.1a 8.Nfd2!? Qd7 9.Nxc4 b5 scores 53% for Black; A1.1b 8.Qe2 b5 9.b3 cxb3 10.axb3 Bd6 scores 56% for Black.

A1.2 7.Nc3 Rb8 8.e4 Be7, with another split: A1.2a 9.Qe2 b5 10.Rd1 Nb4 11.d5 exd5 12.e5 reaches a position that occurs only 20 times in Mega21. Black scores 80% with 12...Nd7, which is the choice of the analysis engines Stockfish13 and Komodo12.1.1, but the sample size is small; A1.2b 9.d5 Nb4 10.Ne5 exd5 11.exd5 Bf5 12.a3 Nd3 13.Nxc4 0-0 scores 63% for Black.

A1.3 7.Bg5 Be7 8.e3 Nd5 9.Bxe7 Ncxe7 scores 61% for Black.

A1.4 7.a4 Rb8, with another split: A1.4a 8.a5 Bb4 scores 60% for Black; A1.4b 8.Nc3 Bb4 9.Bg5 h6 10.Bxf6 Qxf6 scores 67% for Black; A1.4c 8.e3 b5 9.axb5 axb5 scores 71% for Black.

A2 6.Ne5 bb4+ 7.Nc3 Nd5 8.Bd2 Nb6 9.e3 Nbd7 10.Nxd7 Qxd7 scores 63% for Black.

A3 6.a4 Nc6 7.0-0 is a transposition to A1.4.

B) 5.Qa4+ (2,334 games)

After 5...Nbd7, which scores 58%, the line splits.

B1 6.Bg2 a6, after which the line splits again.

B1.1 7.Qxc4 b5, with another split: B1.1a 8.Qc2 Bb7 9.0-0 c5, when 10.a4 b4 scores 78% for Black while 10.dxc5 Bxc5 scores 69% for Black; B1.1b 8.Qc6 Ra7 9.0-0 Bb7 10.Qc2 c5 scores 67% for Black.

B1.2 7.Nc3 c5!? 8.0-0 cxd4 9.Nxd4 reaches a position that occurs only 19 times in Mega21. Black scores 64% with 9...Qc7, which is the top choice of the engines, but the sample size is small.

B2 6.Qxc4 a6 7.Bg2 is a transposition to B1.1.