To complete the transition from Jutsu to Do, Kano added a strict code of ethics to his fighting style. Kodokan instructors and students were expected to be outstanding examples of good character and honest conduct. Fights outside of the dojo or behavior that brought shame to the school would lead to suspension or expulsion. His strict policies were a firm standard for martial artists,

"...judo is a mental and physical discipline whose lessons are readily applicable to the management of our daily affairs. The fundamental principle of judo, one that governs all the techniques of attack and defense, is whatever the objective, it is best attained by the maximum-efficient use of mind and body for that purpose. The same principle applied to our everyday activities leads to the highest and most rational life. Training in the techniques of judo is not the only way to grasp this universal principle, but it is how I arrived at an understanding of it, and it is the means by which I attempt to enlighten others. The principle of maximum efficiency, whether applied to the art of attack and defense or to refining and perfecting daily life, demands above all that there be order and harmony among people. This can be realized only through mutual aid and concession. The result is mutual welfare and benefit. The final aim of judo practice is to inculcate respect for the principles of maximum efficiency and mutual welfare and benefit. Through judo, persons individually and collectively attain their highest spiritual state while at the same time developing their bodies and learning the art of attack and defense."(Dr. Jigoro kano, Kodokan Judo, Tokyo: Kodanshi International, 1986, page 25)