I once asked a high-ranked friend, “What is a shodan? How do you know if a person is a first-degree black belt — or a second or third degree? Does it depend on whether he or she can defeat certain other practitioners of the same art?”
My friend couldn’t answer the question with any conviction. I’d brought it up because I was a member of several promotion committees, each of which had its own criteria for shodan. Even within the same organizations, differences existed.