The belt system is a distinctive feature of judo.  A player can test his ability be entering for examination within a system of grades, and by demonstrating superiority over a cross-section of players at the same level as him/herself he wins promotion to the next rank.  In this way successive ranks become populated by increasingly skilful players until eventually all judoka who participate consistently are distributed through the hierarchy according to their prove ability.

The time-honoured distinction is between kyu (student) and dan (advanced) grades.  Put simply, the distinction marks the point at which the emphasis shifts away from the acquisition of technique on to its effective application.

Promotion with the dan degree does not carry a change of designated colour until 6th dan is reached.  Even then is customary for the holder to continue wearing a black belt in everyday practice, reserving the official colour for ceremonial occasions.  The dan grades are as follows: