Shimuzu sensei, did not appoint a headmaster because it needs two people two practice JoDO. The beautiful point in jodo is when there is rei together. It is easy to hold tachi en jo when you are alone.But for most of the time your partner will not be perfect he will get excited when you hit his suigetsu a little bit hard or to soft.Just look to yourself and at any point in life wether you walk the street or practice jodo you keep your respect for others and this needs practice a lot.There is one important point waza or kata must be the same. timing (Ma) and distance (Maai) allows us to personalize our kata, but in this matter there should be rei. If you carry any form of judgement to your partner old young quick or slow you will learn something different.Grading or Dan in itself means nothing. My sensei 8dan kyoshin has thougt me this language and I am very enjoying myself.
Best regards Bert Sijben