Kodokan Judo was founded by Jigoro Kano, who as a youth began practicing jujutsu as a way to strengthen his diminutive body. Kano studied both the Tenjin Shinyo-ryu and Kito-ryu styles of classical jujutsu, eventually mastering their deepest teachings, and supplemented this training with an avid interest in other combative forms as well. Integrating what he considered the positive points of these with his own ideas and inspirations, he established a revised body of physical technique, and also transformed the traditional jujutsu principle of "defeating strength through flexibility" into a new principle of "maximum efficient use of physical and mental energy." The result was a new theoretical and technical system that Kano felt better matched the needs of modern people.
The essence of this system he expressed in the axiom "maximum efficient
use of energy", a concept he considered both a cornerstone of martial arts and a principle useful in many aspects of life. Practical
application of this principle, he felt, could contribute much to human
and social development, including "mutual prosperity for self and
others", which he identified as the proper goal of training. What Kano
had created transcended mere technique to embrace a set of principles
for perfecting the self. To reflect this, he replaced jutsu (technique)
in the word "ju-jutsu" with the suffix do (path) to create a new name
for his art: judo. His training hall he named "Ko-do-kan," or "a place
to teach the path."