Beat The ... French KIA

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 King's Indian Attack against the French: 1.e4 e6 2.d3 is not generally highly regarded theoretically but is popular at club level and has been used by many attacking players, including Bobby Fischer.

Black scores 45% with the most-popular reply, 2...d5, and 46% with 2...c5, but statistically the best move is 2...b5!?, which scores 50%.

The move, which seems to have been first played by Bent Larsen in 1979, looks bizarre but has a strong positional basis in that it gains space on the queenside - often a black goal in the French - and prepares to develop the problem light-square bishop on a long diagonal.

Position after 2...b5!?

White has two popular replies.

A) 3.Nf3 (69 games)

Black scores an excellent 61% with the obvious 3...Bb7, when there are two main continuations.

A1 4.g3 d6!? 5.Bg2 Nf6 scores 75% for Black.

A2 4.Nbd2 c5 5.g3 Nc6 also scores 75% for Black.

B) 3.g3 (67 games)

3...Bb7 4.Bg2 (4.Nf3 has also been played but is a transposition to A1) c5 scores 48% for Black, at which point there are two main continuations.

B1 5.Nf3 d6!? 6.0-0 Nf6 reaches a much-more mainline KIA position, with the line again splitting.

B1.1 7.a4 b4 8.Nbd2 Nc6 scores 61% for Black.

B1.2 7.Nbd2 Nc6 8.Re1 Be7 scores 71% for Black.

B1.3 7.Re1Nbd7!? 8.Nbd2 Qc7 scores 61% for Black.

B2 5.f4!? d6!? scores 50% for Black.

Note that, unlike previous entries in this series, many of these statistics are based on only a handful of games - 2...b5!? is a very uncommon move.