By Erik Hofmeister
As with every rank, there are expectations of yudansha for time in rank, class hours, learned techniques, and improved techniques. There is also an expectation of WYKKO event attendance and contribution to the dojo and organization. In addition to all these requirements, I imagine several differences among the ranks of yudansha.
Shodan to Nidan is Precision
To me, the primary difference between Shodan and Nidan is precision of technique. The nine new forms required for Nidan have to be nearly flawless, unlike every promotion before, where the new kata merely had to be acceptable to good. The foot position for each stance has to be precise, the hand techniques clear and clean. There are a lot of kata at this rank to help emphasize the precision of each of the techniques. This is a rank to get everything clean and smooth, similar to how I see 4th kyu.
Nidan to Sandan is Understanding
Once you have precision, what more is there to achieve? Obviously the Nidan student has not achieved perfection, but all of their older kata should be performable to a very high degree. What the Nidan student now learns is understanding. Why do the kata do what they do, what is the bunkai for all the kata, and how can that information be best imparted to others? All of these questions and others should dwell in the mind of the Nidan student. They should seek understanding of the motions, and universal principles which can be applied throughout their martial arts. They should understand why the technique is done one way and not another, and how to maximize their efficiency of motion.
Sandan to Yondan is Depth
Once you have begun to question your karate, you find there are unknowable depths to plumb. Thinking about karate becomes part of your everyday life, and the philosophy inside the dojo and outside the dojo become one. You have been doing karate for so long, and in so much detail, that it becomes an important, integral part of your being. You think of yourself fully as a martial artist. You explore the history and talk to others endlessly about karate and martial arts conundrums. No longer are you satisfied by what you can learn in class- you seek depth of understanding in all things karate.
Yondan to Godan is Completion
In most martial arts, there is no curriculum above fifth degree black belt. Once you achieve Godan, you have learned all of the official content of the martial art. Obviously there is more to improve and other things to learn, but there are no more kata, no more weapons, no more paired exercises to learn. Therefore, Yondan is your last opportunity to learn everything you can about the style. You need to ask any high rank you can about the techniques, their interaction with each other, the applications, etc. Obviously after Godan you can still ask these questions, but once you have achieved Godan you will be expected to know the full content of your style.
These differences among ranks were the path I walked, and the one I think best suits most students. Many students probably walk many different paths. I believe these expectations create an appropriate pattern of growth for the Yoshukai yudansha, and lead to the most adept, mature, and well-rounded student. They provide clear goals for the student to work toward, in addition to all the written expectations.