What if Black does not play e5? The Sicilian case

Beginners are often advised to play games starting 1. e4 e5. It is a simple an solid way of playing and nearly everyone starts with those openings, be it the Ruy Lopez or the Italian. For beginners the actual lines are not important, you only need to move according to the opening principles: control the center, develop your pieces (minor pieces first) and castle.

Unfortunately the opponent need not to play accordingly and they may start with a different opening, so the question is how to handle it. I'll go through what opening principles tell about playing against the Sicilian. I will intentionally leave some perfectly playable lines uncovered, this is just a very simple survival guide to someone who does not know the Sicilian. I'm assuming Black knows what they are doing so the Black moves are mainline book moves.

The Sicilian begins with 1. e4 c5. The first question to ask is, does black threaten anything immediately. The answer is no. Next we go to the opening principles. Control the center - the best way would be to play d4 but that pawn gets captured. You can recapture, but that would bring the queen out to be harrassed.

We then move to the next principle, develop your pieces. Usually knights are the ones to develop first, so 2. Nc3 and 2. Nf3 are the moves to consider. These are actually the two most popular moves even at the grandmaster level, called the closed and the open variation of the Sicilian. Which to choose? In general terms, 2. Nc3 leads to slower play in the style of Giuoco Piano, while 2. Nf3 is more of an active battle at the center in the style of the Scotch opening. Choose the one that fits your style.

The closed Sicilian (2. Nc3)

Black will likely respond 2. ... Nc6. Again it does not threaten anything directly. Playing d4 becomes even harder, so you should develop your pieces and make yourself ready to castle. If you want to castle queenside, the obvious plan is to play 3. d3 and then develop the bishop  and move the queen out of the way. If you castle queenside, your general plan should be to attack on the kingside, so you may want to push the pawns first before blocking them with your pieces - but only after you've taken your king to safety.

If you want to castle kingside, you need to think on where to move the bishop and the knight. Moving the bishop to b5 is OK, but only if you want to capture the knight. Otherwise you lose a tempo to a6, since moving Ba4 like in the Ruy Lopez will trap the bishop after b5 and c4. (Nd4 is another move Black can play, then you should just bring the bishop back to e.g c4 as it is attacked.) Bc4 and Be2 are good squares, but Bd3 blocks your d-pawn and makes it difficult to develop the other bishop. However, the most common plan in the closed Sicilian is to play g3 and Bg2, i.e. to fianchetto the bishop.

The knight can be played to f3 or e2, on both squares it controls d4. If your bishop is on g2, on f3 the knight will temporarily block the bishop but it controls more of the center.

Playing 3. Nf3 will be interpreted by Black that you are going to use the back door to enter the 2. Nf3 line (which you of course can do, but need not to), so they will play whatever pawn formation they are heading to, usually 3. ... d6, e6 or g6. The same applies to 3. Be2. The standard reply to 3. Bc4 is probably 3. ... e6, while if 3. g3 is played, Black usually plays 3. ... g6 and also fianchettoes the bishop.

Usually the closed Sicilian does not leave many targets for Black to attack immediately.

The open Sicilian (2. Nf3)

Black will usually reply either 2. ... Nc6, d6, e6 or g6 depending on which pawn formation they like. After 2. Nf3, the d4 square is supported by the knight and the queen, so 3. d4 is by far the most common move, trying to take over the center. Then 3. ... cxd4 4. Nxd4 follows. If Black has played 2. ... Nc6, they usually should not capture the knight as 4. ... Nxd4 5. Qxd4 leaves White with a more active position. As the knight has been traded off, Black cannot attack the queen so easily even if it at the center of the board.

Black's most common move is 4. ... Nf6, which attacks the e4 pawn, so White must react. The best way to defend is 5. Nc3, since 5. Bd3 makes the knight undefended and 5. f3 weakens the kingside pawn formation.

If Black plays quiet moves preparing castling, then the light square bishop needs to be developed before castling. The usual options are Bc4 and Be2, the former being more active. If Black plays e5, you obviously have to do something about the knight. The best move depends on the position. If there is a knight on c6, it can be taken, sometimes Nb5 is the best move (the d6-square is a target sometimes), sometimes it is just safest to retreat.

In any case after these ideas, you should have a solid and playable position.

If your opponent deviates from this, then defend whatever is being attacked, capture anything that is left undefended and develop your pieces and you should be fine. Actual Sicilian theory contains many variations with known lines well into the middlegame (my knowledge of actual lines ends before move 10), but if your opponent is a beginner, too, they will probably not know much more than I've described above.