There is a version of the black belt who believes they have arrived.
I try hard not to be him. Every class, I walk onto the mat as if I am trying to see the position for the first time — not because I have forgotten what I know, but because what I know is a smaller fraction of what is actually there than I used to think. The techniques I drilled for a decade still have rooms in them I have not entered. The positions I teach are positions I am still learning.
I train in Bradenton under Coach Dan Martinez, a third-degree black belt who speaks to his students as equals even when he is the one with the answer. That is not an accident of personality. That is a choice about what a teacher is for. A room where the black belt cannot keep learning is a room where nobody else can learn either. The reverse is also true.
Not every academy is built this way, and this is the hardest thing to communicate to a new practitioner still searching: the environment you train in is as important as how much you train. The platform I am building is partly an answer to this — a way for practitioners to find the rooms where they will still be learning in twenty years, and to recognize the coaches who keep their students' minds open because they kept their own open first.