Weird move order in the Sicilian defense

Hello,

I'm quite new to the e4 world, and someone just played a peculia move order :

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nc6 ?!

The position can arise after Nc6 at move 2 and d6 at move 4. It is quite rare in high level pratice, but it only involes regular moves in the sicilian. Yet in the ressources I have (Negi's book, Saric's course, etc...) on the open sicilian, this position isn't ever mentionned.

I understand that this setup is less forcing (Nf6 on move 4 forces Nc3) but after 5.Nc3, black can play e5 and force a Kalashnikov variation where white cannot play c4. However after c4, black can enter some setups where Bc4 isn't available for white.

As the engines don't find a clear refutation of this move order, I was wondering why this is not a named setup with some theory around it ?

I think the reason why Nf6 is preffered is because 1. it is more forcing 2. Nc6 is usually not as critical as other moves near the start while Nf6 is pretty much always going to be play.

By the way, the OP says 4...Nf6 forces 5.Nc3.  It doesn't!  When I did play e4 and before I was playing the Closed Sicilian (i.e. Pre-pandemic), I played 5.f3.  It is known as the Prins Variation.  Common replies are the endgame line (5...e5 and 6...d5), 5...e5 followed by 6...Be6, 6...Qb6, and then 6...Nc6, the last of which would often directly transpose to the Accelerated Dragon, Maroczy Bind.

4...Nc6 is an invitation to 5 c4.
https://www.chessgames.com/perl/chessgame?gid=1060737 

Thanks for your answers.

So obviosly, 4... NF6 does not necessarly forces Nc3, but it is still a more forcing move than Nc6, that was my point. And i'm guessing that in pratice, 95% of cases people answer Nf6 with Nc3.

I reckon white has a variety of good moves, especially Nc3 and c4, but my question, to answer Ron_Saddleback comment, is the possibility of getting "move ordered", and arriving to a unfamiliar position (like for instance a Kalashnikov where you can't play c4 anymore, -but I guess it's just a Svechnikov without Nf6 then-, or some kind of Rauzer where you played c4).

I've been a d4 player for years now and I'm just trying to play e4 a bit. That's why i'm a bit paranoied about move order issue, as I understood they're much more frequent in d4 openings.

I don't have the books at hand, but I'm pretty sure 4. Nc3 e5 transposes to one of the Kalashnkov lines that Negi does cover.  Maybe like so?

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nc6 5. Nc3 e5 6. Ndb5 a6 7. Na3 b5 8. Nd5 Nge7 9. c4  

If you can't find it, I'll see if I can tonight, but I'm pretty sure I was wondering the same thing a month or two back and found this treated somewhere in Volume II.

Or am I wrong?  I do see in the database, that 6. Nb3 seems to score better than 6. Ndb5.  Maybe there's some way to claim that, without Ndb5, Black's d7-d6 is a wasted tempo?

Just double checked, and that's indeed the line Negi covers in Chapter 20 By move 6 of line B, the game has just transposed to his line for the Kalashnakov.

But even better is 6. Nf5.  This is bad in the usual move orders against both the Sveshnikov and Kalashnakov, where the thematic answer is d7-d5. But if Black has already played d7-d6, then Black is a tempo late and d6-d5 doesn't work.  Instead, they pretty mch have to give up the LSB for the knight on f5, and White gets to put a fabulous knight on d5, with no LSB to chase it away.