Material or Piece Activity?

Here is a game from the Women's section of the 2008 Moscow Open, WFM Kiseljova - WGM Pogonina with full annotations and commentary:

This game is a good illustration of the battle between material and piece activity. Early in the game black sacrificed a pawn and in return got open lines for the pieces on the queenside. Eventually we saw that black was able to systematically improve the activity of the pieces and overtake white on the queenside.

Most players think that the material count is the most important thing in chess but many times this is not the case. If executed correctly a sacrifice of material for a lead in development, piece activity, or open lines can prove to be victorious!