Master Shimabuku died in 1974 but many of his students are still teaching. This is why we study Shimabuku tapes at our Dojo. We also invite Shimabuku trained Masters for seminars and demonstrations.
Our Sensei says that the colored belts are just a way to reward progression thru the katas and learning the history of the discipline. When you reach Shodan it means you are now ready to start doing some learning on your own. Before that you can only learn from a Sensei.