The Sovereign Chess board is designed to give each player equal opportunity to control any color in the game. The board has two squares of each color, placed symmetrically across the board, with one square closest to each player. However, when one player controls a square of a certain color, the other square of the same color can not be occupied by either player.
One obvious outcome is that only one player can control a particular color. However, it also can be used strategically to block certain squares. For example, Figure 21 shows all of the squares that can not be currently occupied by any piece.
Figure 21: Blocked Squares in Current Position
Notice that this includes the other Black square in the middle of the board--even though White does not technically control Black by occupying that square.
There is one other advantage of controlling a square of color, which is seen in Rule #14...