柔道 Jūdō (from year 1913)
Description from www.judoinfo.com
I have high hopes for such from what I take to be a pretty rare book now sitting in my gigantic pile of Things to Read - the Taisho 2 (1913) 'Judo' by Itsuro Munakata 5dan, one of the very first live-in students around 1884 at the Kano juku Private School, a life-long judoka who eventually attained 7dan, and whose photo hangs on the Kodokan museum wall with much more internationally famous judoka.
The book's foreword by Kano shihan goes into detail about the lifelong dedication and hard work of Munakata, who he describes as one of the few who understand judo. Munakata was also an educator, who followed Kano as the headmaster of a number of the numbered high schools in Japan that formed the foundation of Japan's university system.
While I have not read it yet, the table of contents indicates that Munakata delves in the physical and spiritual development of the judoka, the importance of kata, etc., along the path of judo shugyo. Including references to the role of Edo era bushido / Confucianism in judo shugyo, if I understand it correctly at a scan, but I need to read the entire thing in detail to ensure I have it right.