Beat The ... Bird

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.

Bird's Opening: 1.f4 is rare among the elite but popular with club players who hope to get their opponents out of book as soon as possible.

Black has many possible replies, but of those moves in Mega21 that occur at least 200 times, the most successful statistically by a long way is 1...g6, which scores 58%.

One significant point in its favour is that discourages White from following up with an early b3 (some whites would love to play 1.b3 followed by a quick f4 to clamp down on the e5 square, but are put off by the possibility of 1.b3 being met by 1...e5, which is indeed Black's commonest response).

Position after 1...g6

White has three reasonably-common continuations.

A) 2.Nf3 (2,972 games)

After 2...d5!? (Black often avoids playing 1...d5 because it can be met by 2.b3, but with 1...g6 discouraging b3, then the move ...d5 becomes desirable) the line splits.

A1 3.e3 Bg7, after which the line splits again.

A1.1 4.Be2 c5 5.0-0 Nc6, when A1.1a 6.d3 Nf6 (this and 6...Nh6 are equally successful, but Stockfish13 and Komodo12.1.1 much prefer ...Nf6) 7.Qe1 0-0 8.Qh4 b6!? 9.Nbd2 Ba6 scores 79% for Black, albeit from a small sample, and A1.1b 6.d4 Nf6 7.c3 0-0 8.Ne5 Qc7 scores 70% for Black, albeit from a small sample.

A1.2 4.d4 Nh6!?, when A1.2a 5.Bd3 0-0 6.0-0 c5 7.c3 Qc7 scores 87% for Black and A1.2b 5.c4 dxc4!? 6.Bxc4 0-0 also scores 87% for Black, albeit from a small sample.

A1.3 4.Nc3 Nh6!? 5.b3 0-0 6.Bb2 d5 scores 75% for Black, albeit from a small sample.

A1.4 4.c4 Nf6, when A1.4a 5.Nc3 0-0 6.d4 c6 7.Bd3 c5!? scores 80% for Black, albeit from a small sample, and A1.4b 5.cxd5 Nxd5 6.Nc3 0-0 7.Bc4 Nb6 scores 71% for Black, albeit from a small sample.

A2 3.g3 Bg7 4.Bg2 Nh6!?, after which the line splits again.

A2.1 5.0-0 0-0 6.d3 d4!? 7.c3 c5 8.e4 dxe3 9.Bxe3 Qc7 scores 58% for Black.

A2.2 5.d3 d4!? 6.c3 c5 7.e4 dxe3 8.Bxe3 Nd7 scores 79% for Black, albeit from a small sample.

B) 2.e4 (403 games)

After 2...d5!? the line splits.

B1 3.e5 c5 4.Nf3 Nc6 5.c3 Nh6!? scores 80% for Black, albeit from a small sample.

B2 3.exd5 Qxd5 4.Nc3 reaches a position in Mega21 in which Black scores 75% with both 4...Qa5 and 4...Qd6, albeit from small samples.

C) 2.g3 (95 games)

After 2...d5!? the line splits.

C1 3.Bg2 Bg7 4.Nf3 is a transposition to A2.

C2 3.Nf3 Bg7 4.Bg2 is also a transposition to A2.