This book is more recent than Ntirlis, but is it better? Which would you buy?

I don't see how the repertoire could really be streamlined.  I don't have the book in question, but it seems that some move order editing would have cleared up some confusion.  Yes, if you're happy with 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.cxd5 Nxd5 then you should be just as happy with 1.d4 d5 2.c4 e6 3.Nf3 Nf6 4.Nc3 c5 5.cxd5 Nxd5, unless Kornev has some idea in the first line that forces White out of a Semi-Slav. 

Chapters 5 through 10, and let's say specifically 7 through 10, probably should not have given the move order 3.Nf3 Nf6 4.Nc3 Be7 5.Bg5, but rather the more traditional 3.Nc3 Nf6 4.Bg5 Be7 5.Nf3.  In this way, it would be clear that you need to know another QGD defense, and can't simply stick to the Semi-Tarrasch against everything. 

I wonder why he chose to give those move orders?  Was it laziness, sloppiness, or something deliberate and well thought out that I don't see? 

So to Gillbod's question, yes, go ahead and play the Semi-Tarrasch against White bringing his knights out on moves three and four.  But it doesn't really streamline or simplify your repertoire as far as I'm concerned, since White can simply develop his bishop on move four instead, bypassing the Semi-Slav and forcing you into another line anyway. 

I think that the confusion came about because in Gillbod's original post, he said "Mainline with 7...Nbd7" and then later wondered why you couldn't use the Semi-Tarrasch as a weapon against "the mainline."  Well, the problem is that White forces a "Mainline with 7...Nbd7" and avoids the Semi-Tarrasch by simply altering the move order of "the mainline." 

Maybe you are right. It would certainly explain the answers stating that 4.Bg5 is a problem for the Semi-Tarrasch. But I read the OP very differently, to wit:

Given Kornev's repertoire...

Contents
(006) Preface
Part 1.  Queen's Gambit Declined 1.d4 d5 2.c4 e6
(008) ch01 3.cxd5 exd5 4.Nc3  c6
(020) ch02 3.Nc3 Nf6 Rare; 4.Bg5 Be7
(030) ch03 3.Nc3 Nf6 4.cxd5 Nxd5
(052) ch04 3.Nf3 Nf6 (A) 4.Bg5 Be7 (B) 4.e3 Be7
(062) ch05 3.Nf3 Nf6 4.Nc3 Be7 (A) 5.Qc2 c5 (B) 5.e3 O-O
(080) ch06 3.Nf3 Nf6 4.Nc3 Be7 5.cxd5 exd5 (A) 6.Bf4 c6 (B) 6.Bg5 c6
(098) ch07 3.Nf3 Nf6 4.Nc3 Be7 5.Bf4 O-O (A) 6.Rc1 c5 (B) 6.a3 b6 (C) 6.e3 Nbd7 (C1) 7.Qc2 c5 (C2) 7.Be2 dxc4 (C3) 7.a3 c5
(119) ch08 3.Nf3 Nf6 4.Nc3 Be7 5.Bf4 O-O 6.e3 Nbd7 7.c5 c6
(130) ch09 3.Nf3 Nf6 4.Nc3 Be7 5.Bg5 h6 (A) 6.Bf4 O-O (B) 6.Bxf6 Bxf6
(158) ch10 3.Nf3 Nf6 4.Nc3 Be7 5.Bg5 h6 6.Bh4 O-O 7.e3 Nbd7
Part 2.  Catalan Opening 1.d4 d5 2.c4 e6 3.Nf3 Nf6 4.g3 Be7 5.Bg2 O-O
(170) ch11 A) 6.Nbd2 b6; B) 6.Qc2 c5; 6.Nc3 dxc4
(186) ch12 6.O-O dxc4  Rare; 7.Ne5 Nc6
(203) ch13 6.O-O dxc4 7.Qc2 a6 8.a4 Bd7
(219) ch14 6.O-O dxc4 7.Qc2 a6 8.Qxc4 b5
Part 3.  When Winning is a Must 1.d4 d5 2.c4 e6
(237) ch15 3.Nc3 a6 w/o 4.Nf3
(257) ch16 3.Nc3 a6 4.Nf3 Nf6
(277) ch17 3.g3 a6; 3.Nf3 a6
(300) Index of Variations

... instead of 4...Be7 as given in chapters 5-10, wouldn't 4...c5 be more consistent with chapter 3? That is how I read his question anyway.

The OP did use the word "mainline", but I think it's just a consequence of the way Kornev structured the book, with the "mainline" in chapter 10 beginning 3.Nf3 Nf6 4.Nc3, whereas most books would have it as 3.Nc3 Nf6 4.Bg5 Be7 5.e3 O-O 6.Nf3 h6 7.Bh4 Nbd7. Kornev has 3.Nc3 Nf6 4.Bg5 Be7 in chapter 2. I don't think the OP was intending to avoid 4.Bg5 Be7.

Again, maybe you are right, and I simply read too much into the OP's question.

Main line stuff with
1 d4 d5
2 c4 e6
3 Nf3 Nf6
4 g3 Be7
5 Bg2 0-0
6 0-0 dxc4
7 Qc2 a6

LeeRoth wrote on 03/04/18 at 18:20:24:

ErictheRed wrote on 03/04/18 at 18:33:53:

The problem is that his question was about 3.Nc3 Nf6 4.Nf3.

@Gillbod - Yes as you point out 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Nc3 c5 5.cxd5 Nxd5 dove-tails with 4.cxd5 Nxd5. It may be that Kornev feels 4...Be7 5.Bf4 O-O 6.e3 Nbd7 equalizes more cleanly. This sort of question arises in every repertoire: whether to transpose, or instead to "punish" the opponent's move order. Actually it is nice that Kornev presented this line, because now you have a choice whether to follow his repertoire to a T, or vary with 4...c5. It's also nice since if a problem arises with 4.cxd5 Nxd5, now you only have to patch one system rather than two.

FreeRepublic wrote on 03/04/18 at 18:18:51:


I imagine it will be very similar lines to those covered in the excellent Quality Chess book by Ntirlis. In that case, the preferred move order is Be7 / Nbd7 before h6. That way there are no problems with the 6.Bf6 lines you dislike Free Republic, as Nf6 would take away most of the point.

4..Nxd5 is an interesting choice, especially since Korneev thought it was advantageous to White in his earlier book from the White side. 

After 4.. Nxd5 5.e4 Nxc3 6.bxc3 c5, Korneev recommended entering the Semi-Tarrasch with 7.Nf3.  But White can also try 7.a3 and 7.Rb1.  The theoretical verdict of all these lines seems to shift between +/= and =. 

The problem with using the Semi-Tarrasch as a defense to the main line is that it does not work against the traditional move order: 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Bg5.