Chess games can produce five different pawn centres. Pawn centres are characterized by the pawn structures of the d- and e- files. The five different pawn centres are closed, dynamic, mobile, fixed and open.
The closed pawn centre has four pawns on the d- and e-files, two for each side. Because there is little space in the centre, play develops on the wings. In the closed centre, knights are often very useful because they can manoeuvre to squares that other pieces cannot reach.
Another pawn centre with four pawns is the dynamic pawn centre. However, the dynamic pawn centre always develops into another kind of pawn centre. If the pawns become blocked and no exchanges are possible, the result is the closed pawn centre. If the pawns are all exchanged, the centre becomes an open centre.
The mobile pawn centre has three pawns on the board, two for one side and one for the other. As the name suggests, movement of the pawns through the centre is possible.
The fixed pawn centre has two pawns on the board, one for each side. The pawns cannot be exchanged, so movement through the centre is difficult. In a fixed pawn centre, players often try to create strongpoints on the board. For example, if white has a pawn on d4, the strongpoints are c5 and e5.
The open pawn centre has one or no pawns on the board. If there is a pawn on the board, it is a pawn which is not supported by another, so that passage through the centre is unimpeded. With open pawn centres, the king is relatively exposed, so players usually castle early to keep the king protected. Play is usually in the centre of the board.
It is good to be aware of the different pawn centres to determine the type of game which you are playing. If you know the type of pawn centre which your opponent prefers, you may wish to steer the game into a different pawn centre to gain an advantage.