I am proposing a bit of a repertoire here for players who are interested in playing a Slav or Semi-Slav against d4 mainlines, but perhaps don't know quite what to do or what move-orders to use against other moves.

First off, we will assume that this Slav/Semi-Slav is reached by the 1.d4 d5 2.c4 c6 move-order normally, and not by a 1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.Nf3 e6 move-order for example.

1...d5 allows Black to play some critical lines against the side variations (as does 1...Nf6 much of the time) for example:

1.d4 d5

Here White has a wide choice of reasonable moves including:

2.Nc3, 2.Nf3, 2.Bg5, 2.Bf4, 2.e3, 2.g3, and of course 2.c4.

1.d4 d5 2.Nc3 c6 if you play the Caro-Kann is a good line as 3.e4 dxe4 is a Caro-Kann and other moves don't make as much sense but can be met with sensible play. If you don't play the Caro-Kann, 2...Nf6 is obviously fine as well.

1.d4 d5 2.Nf3 Nf6 (This is important if you want to play the critical lines against Torre, London, and Colle setups) and here White has three major sidelines:

1.d4 d5 2.Nf3 Nf6 3.e3 Bf5 This basically shuts down any attempt at a Colle. As I recommend the line 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.e3 Bf5 for Black anyway this fits in with my other suggestions. 4.Bd3 here allows Black to trade his bad Bishop for White's good one. Watch out for queen checks on b5 after trading Bishops on d3. White usually plays 4.c4 here anyway.

1.d4 d5 2.Nf3 Nf6 3.Bf4 c5! 4.e3 Nc6 5.c3 Qb6. This is the refutation of the standard London setup. Black emerges from the opening with a slight advantage in all lines. 6.Qb3 c4 7.Qxb6 (or 7.Qc2 Bf5! with a small advantage due to control over the central light squares. Retain your light-squared Bishop in this line. 8.Qc1 Qd8 is underestimated but very strong.) 7...axb6 with the b5-b4 plan is very good for Black. Na3-b5 can always be met by Ra5.

1.d4 d5 2.Nf3 Nf6 3.Bg5 Ne4. This is a very interesting line against the Torre that usually leads to an equal game. Develop quickly, c5-Nc6 is a typical plan.

1.d4 d5 2.e3 Bf5. Consistent with the above plans. Play will usually lead into something already considered. 3.f4 is an independent but totally non-threatening move. If White trades off light-square Bishops at any point, Black will have the advantage against this Stonewall setup.

1.d4 d5 2.g3 Here Black actually has lots of playable moves: 2...Nf6, 2...c6, and 2...Bg4 are all reasonable as well as 2...Bf5. Pick any of these, and set up your pawns at c6 and d5. You can play Bg4, Nd7 and play for e5, or play e6 with a more solid game.

1.d4 d5 2.Bg5. This move doesn't make sense to me. I usually just play 2...c6, 3...Nd7 and 4...Ngf6 and continue my development.

1.d4 d5 2.Bf4. A somewhat better way to reach the London. 2...Nf6 is consistent. Now 3.Nf3 is met by the above-mentioned 3...c5! but also there is 3.e3 c5 4.c3 Nc6 5.Nd2 Bf5 which is plenty strong. 5...Qb6 6.Qb3 c4 7.Qc2 Bf5 doesn't work here of course as the Rook isn't trapped on a1.

Hopefully this helps and if you have any questions or comments please reply!

This is nice.  I am working on learning Queen's Pawn Game openings, so this was good for me to read.  Thank you

Here's a diagram explaining some of the above lines.

You're right, I posted the wrong Blackmar-Diemer line - replace 3...Nf6 with 3...c6, I don't want to redo the whole diagram.

Great thread Expertise87, as usual.

Let me use it to ask a related question: anybody has the book "Beating 1.d4 Sidelines" by Avrukh, of the Grandmaster Repertoire series?

It's not that I have a particular problem with the systems, but I'd like to understand them better to improve general chess understanding. Can anybody comment on the quality of this book?