Out of book move. This looses whites tempo advantage after 7... Bxe7 8. Bg6 Bg4 9.Be2
7... Bf8xe7 8. Bf1e2 O-O 9. O-O d5
using the extra tempo given by white to expand in the center.
10. Bc1g5 Bc8g4 11. Nb1d2
The pawn on d5 has done its damage and the threat of moving to d4 pushes the knight to the second best square.
11... c5
Taking space in the center that is uncontested by white.
12. Rf1e1
Moving rook to the open file, however the advantage is yet to be seen because white has blocked that file with his bishop and will have to waste another move have any threats.
12... Nb8c6
Developing and linking rooks.
13. c3
Threatens to take space in the center with 14. d4 cxd4 15. cxd4
13... b5
If the pawn push 14. d4 that would open up lines for whites bishop and b5 prepares for c4 as a response to white while keeping whites position cramped.
14. b3
Preparing 15. c4 which white has more control over, however with the pawn chain created makes whites bishop worse.
14... b4
Black wants to lock white on to the light squares.
