Sovereign Chess

Because Sovereign Chess relies on the squares of color, and control of those squares gives control to those pieces (as we will see in later rules), Rule #5 basically prevents a "loop" of a piece trying to control its own color.

An important impact of this rule, however, is on the White and Black pieces, which are not allowed to move onto the squares of their own color in the middle of the board. More than just a nuisance, this rule can provide some fairly clever situations in a game of Sovereign Chess.

Consider the position in Figure 3, where the Black King, near the middle of the board, is being checked by the White Queen. While there are a few spaces of possible retreat, one response is to move to h9, seemingly in line with the queen's attack. Rule #5 makes the White square safe from attack by the White queen--or, for that matter, any other White piece--which removes the check. 

However, this position does not leave the Black King invincible, as it can still be threatened by pieces of other colors which are controlled by the White player.

This rule also creates the following position, where Kings of opposing colors can occupy the other player's square of color, thus making them impervious to capture by each other.

To further clarify movement of pawns, we move to Rule #6...