Catalan Opening: Closed
1.d4 Nf6 2.c4 e6 3.g3 d5 4.Bg2 dxc4 5.Nf3
The 'open' reaction to the Catalan seeks to utilize one of the disadvantages of the Catalan - that the c4-pawn is undefended. Black captures that pawn, requiring White to either expend time regaining it or remain down a pawn.
Pros:
- Black temporarily wins a pawn
- White might have to lose time
Cons:
- The g2-bishop becomes stronger
- White gains an advantage of pawns in the center
- Sacrificing a pawn might bring strong queenside pressure