Introduction:
First thing: we will use this line as our reference.
1.d4 Nf6
2.c4 e6
3.g3 d5
4.Bg2 Be7
5.Nf3 0-0
6.0-0 dxc4
7.Qc2 a6
8.Qxc4 b5
9.Qc2 Bb7
10.Bd2 Be4
11.Qc1
I split, for didactic reasons, the catalan into 3 fields of lines:
a) Main Line (with 6...dxc4)
b) Open Catalan (with 4...dxc4)
c) Others
I used to think there was only 6...dxc4 or the closed catalan 6...Nbd7 or c6 but it's not true.
4...dxc4 is very played too, for the top players.
a) Main Line (with 6...dxc4)
This is a rather interesting position that comes after
1.d4 Nf6
2.c4 e6
3.g3 d5
4.Bg2 Be7
5.Nf3 0-0
6.0-0 dxc4
7.Qc2 a6
8.Qxc4 b5
9.Qc2 Bb7
10.Bd2 Be4
11.Qc1
Here, depending on how black will answer, the best players of world, will move the d2 bishop to a5, g5, e3 or f4.
Can you believe it?!
if 11...Nc6 12.Be3
if 11...Bb7 12.Bf4
if 11...Qc8 12.Bg5
if 11...Nbd7 12.Ba5
But let's not confuse the move 10...Nc6 with 11...Nc6
This is the position after 10...Nc6, instead of 10...Be4
the correct answer is 11.e3 not Be3
10...Nc6 11.e3 Nb4 12.Bb4! (Good move! You must know it too) Kramnik x Carlsen, in 2007
10...Be4 11.Qc1 Nc6 12.Be3
Do not confuse 10...Nc6 with 11...Nc6.!
If 10...Ra7, i suggest 11.Rc1, if 11..Be4 12.Qb3
