3. nc3 vs 3.nf3 in the slav

After 1.d4 d5 2. c4 c6 both 3.nc3 and 3.nf3 are both incredibly common.  

 I know that nf3 is aimed at preventing early e5 ideas. What are other differences in these lines? What is the draw back of nf3? In a vast majority of games I end up playing my N to f3 anyway and if I can avoid learning some albin gambit theory then it seems they way to go.

I have usually dogmatically played 3.nc3 not for any real reason; I just always have. Is there any theory I am avoiding by playing 3. nc3?

What about an even earlier 2. nf3 intending 3.c4 which seems to aim to prevent any chance at all for an early e5 from black except 1...e5. Are there draw backs to this move order.  I suppose it black goes into the QGD instead of slav then you can't play any of the Ne2 ideas in the exchange variation.

Here are some differences

3.Nf3: Probably best if you intend 4.Nc3 (main lines), along with excluding e3, as 3...dxc4 is possible, but not so good. However, if you intend 4.e3 (to protect c4), black can develop with ...Bf5 or ...Bg4 because Nf3 puts less pressure on d5 so cxd5 and Qb3 ideas aren't effective (but 3.Nf3 and 4.e3 is still a good and trendy line).

3.Nc3: Good for playing 4.e3 (a useful idea for avoiding the classical slav, which is 4...dxc4 after Nf3 and Nc3), as 4...Bf5 there is answered strongly by 5.cxd5, cxd5 6.Qb3 with pressure (although besides the passive main line 6...Bc8 there, you may also have to look at the "Glasglow Kiss" 6...Nc6, a tricky gambit that requires good play from white to get an advantage). However, 3.Nc3 allows 3...dxc4 (as ...b5 can be followed with ...b4 to hit the white knight on c3, contrary to 3.Nf3), as well as 3...e5 (the Winawer Countergambit, which is tricky but still nice for white). 

2.Nf3: if you're going to play queen's gambit lines, I don't see much point to this move order. With it, you avoid like the Albin Countergambit (sort of, 2...Nc6 and 3...e5 is still somewhat viable), but you also allow other reasonable options for black like 2...c5 or perhaps even a development of the queen's bishop on move 2 (as well as 2...Nf6, just heading for QG lines). Still, it's not a bad move order of course, especially if you play like the Torre or London against Indian lines.

So overall, it's an interesting debate. If you like to play Nf3 and Nc3 lines, play 3.Nf3 for sure, as you avoid the rather dangerous 3...dxc4 (Against 3.Nc3). However, if you despise the classical Slav (which why would you? White can choose lines to cater to his style of 6.Ne5 (more tactical) or 6.e3 (a little more positional)), try 3.Nc3 and 4.e3 (although it does limit you choice against the Semi Slav to the Meran or Anti-Meran). Of course, there are always specifics...

What a great answer by Schevenadorf!

3 Nf3 works best.  The only possible problem comes on 3...e6 when White faces the possibility of the Abrahams-Noteboom 4 Nc3 dxc4.  Theoretically, White should be fine, but Black scores heavily.

1.d4 d5 2.c4 c6 3.Nf3 e6 and White has several reasonable alternatives to 4.Nc3 if he wants to avoid the Noteboom.  From Black's perspective I found 4.Qc2 to be the most annoying one.

Hey Jonathan,

Nc3 Plusses:

Avoids 4. e3 Bf5/Bg4 as opposed to 3. Nf3 Nf6 4. e3 Bf5/Bg4, Allows Marshall Gambit.

 Minuses:

Allows the Albin, Allows dxc4, can't go Nd2 to avoid the Meran as in 3. Nf3 e6 e3 Nf6 Nd2.

Nf3 plusses:

Avoids 3.. dxc4 complications, Avoids Albin, Allows Nd2 lines

Minuses:

Allows Bf5/Bg4 if you intend to play 4. e3

IM Spinaltap, I get the feeling when you say "Albin" you mean Winawer Counter Gambit 1 d4 d5 2 c4 c6 3 Nc3 e5.

A beginner question: How is 3. Nf3 avoiding dxc4? Can't black take anyways on c4?

In the classical theory of openings 3. Nf3 dxc4 is considered more favourable for White than 3. Nc3 dxc4 (because b5-b4 will kick the Nc3 away), and therefore Black plays dxc4 far more often after 3. Nc3 than after 3. Nf3 (5% vs 1% in master games), that was the general meaning.

Ah this is an important question, which also comes into play in other more complex openings, like the Catalan!

When white plays Nf3, he is guarding the d4 pawn (overprotecting it), therefore the queen on d1 can move to attack a pawn on c4, for example, without allowing black to take the pawn on d4 with his queen.

A knight on c3 does not guard d4, and a knight on c3 can also "interfere" with white being able to win the pawn back after the move ...d5xc4, since Qc2 is no longer possible. So usually white has to play moves like e3 (if black captures on c4 too early, example: if the move ....c7-c6 is not played to take control of the b5 square) or pawn a2-a4, to stop black from defending the c4 pawn with ...b7-b5. With a pawn on c6, the move ...b5 gains in strength.

In many Catalan opening lines, white often keeps the queen knight on b1, precisely so that he can respond to black playing ...d5xc4 with Qc2, since the c-file is not blocked by a knight on c3. Since white's f1 bishop goes to g2 in the Catalan, he has to have another way to handle the threat of ...dxc4, so he delays development of the b1 knight until after castling and maybe after the move Qd1-c2.

The "Meran" system is also a valid system: where white plays Nf3, e2-e3 and then Nc3 and black does not try to move ...Bf5 and instead keeps the bishop in the pawn chain with ...e7-e6, leaving both white and black queenside bishops locked behind pawns. Another main line of the slav involves White playing the same e3 move (with bishop on c1) and then after ...Bf5, then White plays Nc3, followed by going for the bishop pair by attacking the f5 bishop with knight f3-h4 (since black has almost always played ...Ng8-f6).

We don't talk about the Bg5 dxc4 e4 b5 "Botvinnik" variations here, unless you want to memorize 20 moves of theory

Wow that's helpful 😎

Some good analysis here. The one thing I'll add is if you want to play an exchange slav line the 3. Nc3 Nf6 4. cxd5 cxd5 move order is good, it circumvents many interesting responses black can play via 3. cxd5 cxd5 4. Nc3 Nc6... and it also leads to 5. f3 which is a good sharp line. But you do need to be prepared for 3... dxc4 which is a serious line if you aren't prepared

Kasparov said something to the effect that the drawback for Black in the Queen pawn games is how to develop the c8 Bishop. The Slav and Semi-Slav allow for White the chance to limit the scope of the Bishop. If Black goes to f4 early, White can offer to exchange on d3 and if an early move to g4, White can try not only Qc2 but also Qb3 to pressure the b7 pawn and make c6 a target or at least a backward pawn. Personally, I tend to only get the Slav and Semi-Slav in limited games but I tend to play Nf3 to protect d4 and target e5, again with the idea of trying to hit at c6 and swinging around to the King side before Black can get a good King side attack.