chi-ca said:
At what point does a black belt become a "Master" and when does a Master become a "Grand Master"?
Let me try to answer these. If my answer become a stupid ramble I apologize..
in the Dentokan system, the black belt levels aren't really master levels at all. To earn your black belt, you have to learn and be proficient at the Shodan-gi set of techniques (about 20++ techniques), then to earn 2nd degree black you have to learn the Nidan-gi, for 3rd Black you learn Sandan-gi, and for 4th black you learn Yondan-gi. So even a 4th Dan black is still considered as student level
After 4th Dan, you can take the "instructorship" level or the "shihan-gi", and if you pass this, you will get the teaching license called "shihan menkyo" which basically means "master instructor". So, no, you are not a Master in the sense that your student are your slaves. You are a "master instructor" never separate the master part from the instructor part. You are an instructor whom are authorized to teach advanced techniques ("master class"), hence, you are "master instructor".
After the "shihan menkyo" if you are so addicted to the Hakko-ryu of Dentokan, you will be allowed to learn the "menkyo kaiden" level, which is the rest of the teachings. Kaiden basically means "all transmissions", so after completing this, you have learn everything there is to learn from this school. Thus you are a "menkyo kaidensha" which roughly means "graduate".
No, you don't get grandmasterships here
However it's a common practice to call the teacher of the "master instructors" as "grand master", which basically means "he is the teacher of us all". In our group, this can be used to refer to Mr. Roy Hobbs because he is the teacher of all of our teachers. However he never use that title so we refer to him as simply "Hobbs sensei".
My teacher Ben Haryo (who studied under Mr. Hobbs) also studied Wado-ryu under Mr. Taman. So when Mr. Haryo use the word "grandmaster" or "GM" he refer to Mr. Otsuka Jiro, the son of Wado-ryu founder Mr. Otsuka Hironori. Mr. Otsuka Jiro is the "grandmaster" because his father has chosen him as the grandmaster and successor of the Wado-ryu. Even though my teacher is now under an organization which broken away from Mr. Otsuka Jiro, he still out of respect refer to Mr. Jiro as the grandmaster.
Och I am rambling again! Sorry! must be too much eating American steak!