White: 64Squaresofpain, Black: moonbus, initial ratings within 50 points; notes by moonbus
1... d5 2. c4 c6 3. Nb1c3 e6
D31 QGD Semi-Slav Defense.
4. Bc1f4 dxc4 5. e3 b5 6. a4 Qd8b6
Black has the option of trying to hang onto the extra pawn with a favorable endgame, or returning the extra pawn at some favorable moment.
The absence of the Black Q from the center has temporarily weakened d6; White aims to invade there and prevent Black from castling.
7... Bf8b4 8. Ne4c3
This retreat not only costs White a crucial tempo, but the pin will be a nuisance for White for a while.
Black now threatens to pile up pressure on the pinned N by playing ... Nd5 or ... Ne4. White must bolster the pinned QN.
It was either this or Rc1. This blocks in the KB. White not only lost a tempo and a pawn, he is getting into a cramped position as well. Black has already equalized.
9... Nb8d7 10. g3
Slow, but there was no other way to develop the KB.
10... Bc8b7 11. Bf1g2 O-O 12. O-O a6
Black has completed his development and now shores up the Q-side. Positional assessment: White's 'system' has in no way hindered Black's natural development; Black has comfortably equalized. Black has secured a pawn extra, has a solid pawn structure, no marked weaknesses, and favorable prospects for an endgame on the Q-side. White is compelled to mount a direct attack in the middle game, either in the center or against the Black K-position; if White fails, the endgame will favor the Black Q-side majority.
13. Qd1c2 c5
Black begins mobilizing the Q-side majority, and also activates the QB to challenge White's control of the long diagonal.