Sicilian Defence (Alapin Variation)

With 2. c3, White supports pushing the pawn to d4. It is an "anti-Sicilian", a sideline that White plays to avoid the theory-heavy, classic open Sicilian lines.

If 2...Nc6!?, which is a common amateur try, 3. d4 cxd4 4. cxd4 and White has achieved a two-pawn centre. When they played 1...c5, Black had hoped for an edge by taking central pawn with a less-important flanking c-pawn, but this disappeared when White was able to recapture with their own flank pawn.

The line continues 4...d5 5. exd5 (5. e5?! allows Black to play ...Bf5 and ...e6, for an enhanced French defence structure) Qxd5 6. Nf3 e5 7. Nc3 Bb4 8. Bd2 Bxc3 9. Bxc3 e4 10. Ne5 Nxe5 11. dxe5 Ne7⩲

2...d5 used to be the standard move. This threatens 3...dxe4, and after 3. exd5 Qxd5, the Barmen defence, White can still play 4. d4, but they no longer get two pawns in the centre and Black has a development lead. White is unable to develop Nc3 with tempo on the queen because they have already occupied that square with c3, and Black wishes to delay cxd4 until White has committed the knight somewhere else, so as to avoid c3 becoming available.

2...Nf6 has gained popularity and is now main response. The main line follows with 3. e5 Nd5 (3...Ne4? 4. d3! traps the knight) 4. d4 (threatening 5. c4 & 6. d5) cxd4, transposing into a Smith-Morra gambit declined. 5. cxd4 (or 5. Nf3 Nc6 6. cxd4) is usually met with ...d6, preparing to chip away at the pawn chain. Although not as aggressive for Black, it allows for a more solid structure going into the middle game.

2...d6?! is occasionally played, where Black just allows White to take the full centre, as is 2...e6!? with the idea of 3...d5.

Named after Semyon Alapin, the opening didn’t become popular until the latter 20th century. It was initially thought that the response 2 ...d5 was too strong a position for Black, but modern analysis has shown it to be more favourable for White.

Today it is a popular anti-Sicilian. In the same vein is the delayed Alapin: 2. Nf3 followed by 3. c3. By delaying c3, Black faces different choices depending on how they moved, e.g. 2. Nf3 d6 3. c3 and were Black to play ...d5, as they might against 2. c3, they have lost a tempo.

For explanation of theory tables, see theory table and for notation, see algebraic notation.

1. e4 c5 2. c3

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• The Alapin (c3) ⎸Sicilian Defense Theory - HangingPawns (YouTube)

Wikipedia has related information at Sicilian Defence, Alapin Variation.