Okuden training is focused on the highest level of proficiency in the arts. Even with a lifetime of training, only a small number of truly dedicated martial artists achieve this level of proficiency.
This text is much like The Book of Five Rings by Miyamoto Musashi and The Art of War by Sun Tzu. Okuden is not only focused on combat strategies, but also is focused on natural laws and how your body adapts to changing environments. A much deeper analysis of movement and motion.