Are you allowed to do that? My opponent called me off on that, and I argued with him that it is allowed. The reason being is that I watched a Lin Dan match once where he constantly stands on the middle white line while serving. He's still the right side, of course, but a part of his foot is on top of the service center white line without a part of his shoe going out of the 1.5 inch border line. The commentator, Gillian Clark, even mentions it, and that's why it stuck on my mind ever since. I just can't remember what match it is though.