Absolutely it doesn't, nor did I mean to imply that it actually is the same. I using the term in more of a 'head of system' way (only the head of the system is tenth dan) rather than as a tenth dan being a literal soke. But no, soke and dan are unrelated.Just to clear up a few things here, 10th Dan in no way, shape, or form equals Sokeship. At all.
Pretty much. Though in some systems there is; taekwondo has new pumse for each dan grade. But from what I understand, most systems pretty much are done with new material by fourth.To answer Himura's question, most typically there is no new material beyond about 4th or 5th Dan in most systems, so there wouldn't be a case of "knowing the material through to 9th Dan" in the first place.
Daniel