Beat The ... Sicilian Alapin

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 Alapin (or c3) Variation of the Sicilian: 1.e4 c5 2.c3 is popular at most levels of chess, but particularly among club players.

The best response, statistically, is 2...Nf6, which scores a very good 52%. After 3.e5 Nd5 White has four moves that each appears more than 1,000 times in Mega21.

Position after 3...Nd5

A) 4.d4 (29,734 games)

After 4...cxd4 the line splits.

A1 5.Nf3 d6 (5...Nc6 and 5...e6 are more popular, but their scores of 51% and 52% respectively lag behind the 53% of 5...d6), after which the line splits again.

A1.1 6.cxd4 Nc6 7.Bc4 Nb6, when A1.1a 8.Bb5 Bd7 9.Nc3 dxe5 10.dxe5 g6 scores 61% for Black while A1.1b 8.Bb3 d5 9.Nh4 e6 10.Nf3!? Be7 scores 53% for Black.

A1.2 6.Bc4 Nb6 7.Bb3 d5, when A1.2a 8.cxd4 Nc6 is a transposition to A1.1b while A1.2b 8.Nxd4 Nc6 reaches a position that only occurs 10 times in Mega21, with no consensus on how White should proceed (four games saw 9.f4, four saw 9.Bf4 and two saw 9.Qe2, while my main analysis engines Stockfish13 and Komodo12.1.1 suggest 9.0-0!?).

A1.3 6.Qxd4 e6 7.Nbd2 a6!? 8.Nc4 reaches a position that only occurs 17 times in Mega21. Most popular is 8...Nc6 but the engines reckon 8...dxe5!? gives Black a tiny edge.

A1.4 6.exd6 e6!?, when A1.4a 7.Nxd4 Bxd6 scores 57% for Black while A1.4b 7.cxd4 Bxd6 scores 61% for Black.

A2 5.cxd4 d6, after which the line splits again.

A2.1 6.Nf3 is a transposition to A1.1.

A2.2 6.Bc4 Nb6, when A2.2a 7.Bb5+ Bd7 8.e6!? (this is much more popular than 8.Bxd7+ Qxd7, which scores 61% for Black) fxe6 (8...Bxb5 9.Qh5! reduces Black's score to 51%) 9.Bd3 g6 scores 63% for Black while A2.2b 7.Bb3 Nc6 8.exd6 (almost as popular is 8.Nf3 d5, which is a transposition to A1.1b) e6!? scores 67% for Black.

A2.3 6.exd6 Qxd6 7.Nc3 Nc6 8.Nf3 g6 scores 65% for Black.

A2.4 6.f4 dxe5!? 7.fxe5 (there are four games in Mega21 with 7.dxe5, but the engines reckon Black has at least a slight edge after 7...e6 or 7...Nc6) Nc6 scores 73% for Black, albeit from a small sample.

A3 5.Qxd4 e6, after which the line splits again.

A3.1 6.Nf3 Nc6 7.Qe4 Qc7!?, when A3.1a 8.Nbd2 f5 9.exf6 Nxf6 scores 67% for Black while A3.1b 8.Bc4 Nde7 9.Bf4 Ng6 10.Bg3 b6 scores 57% for Black, albeit from a small sample.

A3.2 6.Bc4 Nc6 7.Qe4 d6, when A3.2a 8.exd6 Nf6 9.Qe2 Bxd6 10.Nf3 Qc7 scores 70% for Black, albeit from a small sample, while A3.2b 8.Nf3 Nb6 9.Bb3 Qc7 scores 71% for Black.

A4 5.Bc4 Qc7 6.Qe2 Nb6, after which the line splits again.

A4.1 7.Bd3 Nc6 8.Nf3 g6 scores 72% for Black.

A4.2 7.Bb3 Nc6 8.Nf3 d5 9.exd6 Qxd6 scores 69% for Black.

B) 4.Nf3 (7,997 games)

After 4...d6 the line splits.

B1 5.d4 cxd4 is a transposition to A1.

B2 5.Bc4 dxe5 6.Nxe5 e6 7.0-0 Bd6 8.d4 0-0 scores 50% for Black.

B3 5.exd6 e6!? 7.d4 cxd4 is a transposition to A1.4.

C) 4.Bc4 (1,493 games)

After 4...e6 the line splits.

C1 5.Nf3 b6!?, after which the line splits again.

C1.1 6.0-0 Bb7 7.d4 cxd4 8.cxd4 Qc7 scores 53% for Black.

C1.2 6.Bxd5!? exd5 7.d4 reaches a position that only occurs 22 times in Mega21. Black has tried five different moves, but the engines like 7...d6, which they reckon gives equality.

C1.3 6.d4 Bb7 7.0-0 cxd4 is a transposition to C1.1.

C2 5.d4 d6 6.Nf3 cxd4 7.cxd4 and now 7...Nc6 scores 50%, but so does the lesser-known 7...Be7, which is preferred by the engines. After the further moves 8.0-0 0-0 9.Qe2 b6 the line splits again.

C2.1 10.Nc3 Nxc3 11.bxc3 Bb7 scores 63% for Black.

C2.2 10.Rd1 Bb7 11.Bxd5!? Bxd5 12.Nc3 reaches a position that only occurs 12 times in Mega21. Black usually plays 12...Bxf3 but the engines prefer the apparent-novelty 12...Bb7!?, although they reckon White may have a slight edge.

C2.3 10.Bd2 Bb7 11.Nc3 Nxc3 12.Bxc3 Nd7 scores 69% for Black.

C2.4 10.Qe4!? Ba6!? reaches a position that only occurs 21 times in Mega21, with no White reply occurring more than seven times. Black scores 57%.

C2.5 10.Nbd2 Bb7 11.Ne4 dxe5 12.dxe5 Nd7 scores 57% for Black.

C2.6 10.Bxd5!? exd5 11.Rd1 reaches a position that only occurs 14 times in Mega21. Stockfish13 reckons 11...Be6 gives equality (it scores 62%, but from only four games), while Komodo12.1.1 prefers 11...Na6 (it scores 50%, but from only five games).

D) 4.g3 (1,033 games)

After 4...d6 5.exd6 Qxd6 6.Bg2 Nc6 the line splits.

D1 7.Ne2 g6!?, after which the line splits again.

D1.1 8.Na3 Nc7!? Bg7 scores 73% for Black, albeit from a small sample.

D1.2 8.d4 cxd4 9.Nxd4 Qe5+ scores 73% for Black, albeit from a very small sample.

D2 7.Na3 Bf5 reaches a position in which no reply occurs more than eight times in Mega21. Black scores 69%.

D3 7.Nf3 Qe6+!? 8.Qe2 Qxe2+ 9.Kxe2 Bg4 scores 67% for Black, albeit from a small sample.