Does anyone know where the time frames between kyu gradings and minimum years between Dan gradings in Karate came from?
Was it adopted when Karate was formalised like the belt system and gi or was it implemented later?
Also what do Karateka think of the time frame system in terms of it's relevance, prupose, standard setting etc? Do you follow it or use a different system for gradings?
What do other arts use as a form of grading?
Many thanks for your help