The only rule is that everyone must follow his rules.

The only rules here are those between a man and woman.

The only rule is to encourage but not to force.

The only rule was that there could be no more than five cities at once.

Her only rule about writing is to never eat chocolate at the computer.

It is the only rule for Christian faith and practice.

The only rules with a defensive game is to save every point.

The only rule is that the people inside the tower may not fall in love with each other.

The only rule will be that everyone has to have fun.

Since the middle 80s that has been the only rule.