Very few books carry a proper explanation of why black can’t play 4. … Bf5 after 1.d4 d5 2.c4 c6 3.Nc3 Nf6 4.Nf3. Most just say that the move is bad because of the reply 5. cxd5 cxd5, 6. Qb3! and white is clearly better. (One or two even advocate 5. Qb3.) The question is; why is white clearly better after 6. Qb3? Black isn’t really behind in development and it looks like he can just play 6. ... b6. What’s wrong with that? If you are one of the many people who have searched in vain for the answers to these questions then this page is for you! We’ve had a good look at the position after 4. ... Bf5 and below we present our conclusions. We are grateful to our silicon friends for pointing out so many of the valuable resources available to white in the following variations. If you have any suggestions for alternatives for black or better ways for white to prosecute his attack then please let us know. Either leave a message in our guestbook here or e-mail us at chyss[at]yahoo[dot]co[dot]uk.
1.d4 d5 2.c4 c6 3.Nc3 Nf6 4.Nf3 Bf5 5.cxd5! I think that this is definitely better than 5. Qb3 because the latter allows black to play 5. ... Qb6, which, though it does not completely equalise, does let black off the hook to a certain extent. After 5. cxd5 we consider two possible responses: 5. ... Nxd5 and 5. ... cxd5.
A) 5. ... Nxd5 may be black’s best option here but white has a couple of promising continuations available:
A1) 6.Qb3 6.e3 e6 7.Bd3 Bxd3 8.Qxd3 and white is doing well. He will soon play e3-e4, liberating the c1-bishop and obtaining a nice big centre.
A2) 6.Nd2 Nxc3 7.bxc3 e6 8.e4 Bg6 9.Bd3 Be7 10.f4 is another idea and also looks quite strong.
B) 5. ... cxd5 6.Qb3
B1) 6. ... Bc8 is possible but after 7.Bf4 e6 8.e3 Nc6 9.Bb5 white has a significant lead in development and ought to be able to make something of it.
B2) 6. ... Qb6 is also possible but after 7.Nxd5 Nxd5 8.Qxd5 e6 9.Qc4 Nc6 10.a3 Rc8 11.e3 white is a pawn up and black’s development lead is probably not sufficient compensation.
B3) 6. ... b6
B31) 7.Bg5 has been played here. The game Epishin - Vandenbempt 2003 continued 7. ... e6 8.e4 dxe4 9.Bb5+ Nbd7 10.Ne5 1–0 which at first sight looks fairly convincing. 9. ... Ke7 has to be checked out but after 10.Ne5 Qxd4 11.Nc4 a6 12.Rd1 Qc5 13.Be3 black either loses his queen or gets mated. However, black can deviate earlier with 7. ... Be6!?. After 8. e3 a6 9. Rc1 Nc6 black’s position, though it’s clearly not very good, is on the verge of being viable. For example, 10.Bd3 h6 11.Bf4 Na5 12.Qc2 Nc4 13.0–0 g5!? 14.Bg3 Bg7 15.b3 Nd6 16.Ne5 0–0 17.a3?! b5 18.Nc6 Qd7 is probably only +=. White is doing well in many of the lines following 7. ... Be6 but we haven’t found a forced win yet. If you can find it, please let us know!
B32)7.e4! is probably the best move. After 7. ... dxe4 8.Ne5 we will look at three tries for black.
B321) 8. ... Qxd4?? is, of course, terrible. White has three obvious and good moves to choose from. 9. Qxf7+, 9. Nxf7, and 9. Bb5+ are all winning for white. For example, 9. Qxf7+ Kd8, 10. Bf4 sets up some very unpleasant threatens including Rd1 winning black's queen, and Qb3 threatening Nf7+ winning the h8 rook.
B322) 8. ... Be6 is certainly worth a go if you end up in this difficult position, as white must play precisely to achieve anything concrete. We believe that best play runs 9.Bb5+ Nbd7 10.d5 Bf5. We’ve spent some time on this position and the best we can come up with is 11.h3. We know it looks a tad slow but black is in no position to untangle himself so white can afford to take his time. Even if 11.h3 isn't the best move, it's still enough to give white at least a clear advantage.
B3221) 11. ... h6 12.g4 Bh7 13.g5 hxg5 14.d6 Bg6 15.Nd5 and white wins material because the knight on f6 is distracted from its defence of the knight on d7 and black can’t bring his bishop to the rescue because of discovered attacks on f7.
B3222) 11. ... h5 12.Bg5. The thing to realise about this position is that black cannot get himself developed. The bishop on f8 is stuck there and as a result black cannot get castled. This means that he cannot escape from the pin on the a4-e8 diagonal which in turn leaves white with plenty of time to find a way of breaking through. For example, if black tries the obvious 12. ... g6 then he gets crushed as follows; 13.d6 Be6 14.Bxf6! Bxb3 15.Bxd7+ Qxd7 16.Nxd7 Kxd7 17.Bxh8+- Black has no compensation for his material deficit. Equally, 12. ... e6 is out because the pin it creates on the h4-d8 diagonal is more than black's position can stand. E.g. 13.Bxf6 gxf6 14.Bxd7+ Qxd7 (14. ... Ke7 15.Qb4 checkmate) 15.Nxd7 +-
B323) 8. ... e6 9.Bb5+ Nfd7 10.g4 Bg6 11.h4 a6 12.Bxd7+ Nxd7 13.h5 Nxe5 14.dxe5 e3 15.hxg6 exf2+ 16.Kxf2 Qd4+ 17.Be3 Qxe5+- The displaced position of white's king is irrelevant as black has not even a ghost of an attack against it. White is a piece up and is clearly winning.
So there you are. Now you know why black shouldn’t play 4. ... Bf5 in the main line Slav!
Once again, our thanks go to our silicon friends for their pertinent and interesting suggestions.