I had the opportunity to travel to the SKA headquarters dojo between Santa Barbara and Ventura to train with Shihan Oshima Sensei. There were two classes, first a morning Brown Belt practice lead specifically by Oshima Sensei, then an afternoon all-ranks session lead by Mori Sensei with a lot of input from Oshima Sensei.
During the Brown Belt practice, we did some kihon and reviewed the kata Basai. In the later session we did some more kihon, sanbon kumite, and my rank group worked on Heian Nidan. Notably, he corrected my initial Heian Nidan block, adjusting my upper (horizontal) arm to be a little lower in order to be much more effective. The principle difference that I felt internally was a transferring of the power from the the upper shoulder muscles to more of a core muscles focus. Some other key points were the importance of rounding the shoulders, focusing the strength forward, not backwards out the shoulder blades, and of placing the center of balance in the correct location in front and back stance to avoid sweep susceptibility and ensure smooth movement.