I believe part of your question was why is it higher than black. I have no way off of the top of my head to confirm the traditional reason, which may have something to do with colored sashes or belts being used for military ranking in Okinawa or Japan before the creation of the belt system for any of the martial arts. The explanation I have heard and always liked, was that the white in higher belts represents a return to the "clean slate" of being a white belt and the understanding that despite ones level of proficiency there is always more to learn, and the red represents the martial artist "bleeding" for the art, or the giving of themself for the progress of their art. Honestly, depending on your art, style, and organization there may be many different "black belts" to represent various titles or certifications held by the wearer and the same belt my mean different things from one art, organization, or style to the next.
