Plans in the Sicilian Defense when opponent plays strange moves

Hi, recently I've started playing the sicilian defense as black because of Daniel Naroditsky's recommendation in his latest speedrun, however at my rating range no one plays the main lines. They always play some strange move such as 1. e4 c5  2. d4 cxd4 3.Qxd4 , or something like 1.e4 c5  2. c4. i know how to punish the Bowdler attack, however when they play other lines such as the ones i mentioned, i find that i get lost and dont really know the plans and tend to blunder a lot because I'm not familiar with the positions. I was wondering if someone can help me understand the plans i need to keep in mind in these types of situations. Also in the topic of the Sicilian Defense, how to you deal with space disadvantage?

OK-- I'll try to summarize and others will surely correct me and fill in stuff I omitted:

so

1. e4 c5 2 d4 cxd 3. Qxd4 you just play Nc6 and play a tempo ahead in whatever Sicilian you were planning.

and if

1. e4 c5 2. c4  You have choices. I'd start with 2.... Nc6 and now an OK plan is if they play 3. Nf3 to now play 3. ... e5 and you are already very very slightly better as the king knight belongs on e2/e7 in that structure. You can also play

3.... Nf6 e6 and d5 even without counting as you can play Nb4 to recover the pawn on d5 in time and if they play e5 you can win the pawn.

Against bad moves in the open Sicilian you can often win a tempo / pawn and just play a normal game.

In the closed you need to know a small number of structures.

Others: against 1. e4 c5 2. Bc4 you play to lock out that bishop by e6 then d5 and maybe even a6, b4 c4 then you are a piece up in the center and kingside and play to win the game there.

In lines like 1. e4 c5 2. Nc6 Nc6 3. f4 g6 4. Nf3  Bg7 5. Bb5 the idea is you hit it immediately with Nd4 and are equal.

Alapin: 1. e4 c5 2. c3  you can play Nf6 or d5 but need to know a little bit after that and pick which you prefer. Alapin is pretty equal if you know a little bit.

Morra 1. e4 c5 2. d4 cxd 3. c3  you can transfer to Alapin by 3... d3 or just accapt the pawn and play a sort of normal Sicilian with an extra pawn. I know one game in the Morra : Ken Smith vs Larry Evans  and it's been enough to get good results vs Morra (plus being good at Sicilain positions and endgames of course)

Have fun!

-Bill

When confronted with strange moves, slow down and assess the importance of the move.

2 moves in, it's hard to immediately take advantage of something. Stick to principle, not autopilot: develop, get your king to safety, and control the center.

Thanks a lot!! I really appreciate it. I will defenitely keep all these points in mind.