What is the difference between sumos with white belts and sumos with black belts?

Answer 1

Many styles have an age limit associated with being able to test for black belt. As such those students that show the necessary skills, but not the age and maturity that comes with it, for a black belt may be given the Junion Black Belt ranking until they reach the appropriate age. Some styles the requirements are the same, in others, a couple of additional kata are necessary to test for the full black belt level.

Answer 2

The color of the belt in sumo is purely decorative and does not indicate any difference.