The reason why Kano Sensei came up with a standard uniform for the practice of Kodokan Judo was to remove class distinction. Prior to this, Jujutsu and other martial arts practitioners trained in what was basically their street clothes. As you might expect, how one dressed would reflect upon their station in life. So if you have a wealthy practitioner, you could expect that they would be better dressed to train than say a poor farmer. However, Kano Sensei wanted Kodokan Judo to be practiced by everyone, rich and poor, as a means of physical education and to the betterment of society. By putting everyone in the same white, non-descript uniform, you could not tell a rich Judoka from a poor one. Trainees would be judged on the merit of their training and effort, and not on what social class to which they belonged.

Dr. Kano was a teacher of the elite, he instructed members of the Japanese royalty, whose children considered this PhD renaisance man equivalent to one of their butlers and treated him as such, at least according to Dr. Kano's autobiography. This first hand experience at snobbery made him consider the class distinction to be suspect, even in his day. Dr. Kano was obviously a man of vision and very ahead of his time - a true innovator and genius on the level with DaVinci, Newton, Liebniz, Godel, Freud, and Planck!

Also remember the time period we are talking about. Japan was just entering the "modern era" and was making an attempt throughout their culture to throw off their class distinction in all areas. The abolishment of the warrior class (bushi) was just part of that process. However, those that had become used to their higher class distinction went out begrudgingly . Kano Sensei's desire to blur the lines of class within the Kodokan was not only in keeping with his own philosophy that "judo was for everyone", but also followed the trend in the new modern Japan.

Based on this, I would speculate that the reason a white judogi was used, rather than a variety of colors, is because it was a plain and inexpensive cloth in with to make the dogi. The Japanese had the dying of cloth in indigo to a real artform. So the availability of a blue dogi (more than just about any other color) was certainly there. However, the dying process was extensive, and the resulting material was quite expensive. So if multiple colors were allowed, and a Judoka of that day wore an indigo judogi, it could be reasonably assumed that this person was wealthy. So you lose the class distinction transparency.

So therefore if everyone today switched over to the blue judogi, the same would hold true - no class issues, just people training in uniform. Dr. Kano hit the nail on the head, the white judo gi is a very good idea. The Japanese were, and still are, a class society.

The white judo gi was not only a product of such empirical reasoning , but a spiritual one as well. Dr. Kano was also a religious man, and saw judo as a way of spiritual, as well as 'character' development.

QUOTE:

In judo, the beginning is 'white' (white belt), but also the ultimate top rank (the 12th dan) is equally a white belt; thus the end point equals the beginning. The color white is seen in the gi, but also in the white stripe on the joshi obi 'female belt). The female is where life begins. Similarly, it is the color of ososhiki, a funeral or death. The end is the beginning.

The samurai preparing to commit seppuku wears a white kimono. White is also the color of purification, of pure intentions and of honor, a color that illustrates one is no longer occupied by the ego. It is the color of void or emptiness. Judo's second principle (ji-ta kyo-ei or mutual prosperity) does no longer deal with one's own, but with how you can be at the service of others, how you can contribute to one's happiness. In essence reaching the stages, per definition is beyond the ego still interested in materialism or obtaining medals or results. It is about how can I contribute to humanity. Deviating from the color in essence rejects the second principle, argues, in service of the ego instead of others.

Strictly speaking even a modern bleached white gi is a deviation. In judo, the principles of of wabi, sabi, yogen and mono-no-aware receive attention in Itsutsu-no-kata and Koshiki-no-kata, some of the most advanced stages of judo. 'Wabi' in English, more or less means simple, subdued, austere beauty Color-wise this implies an adherence to something which could be the creation of nature, natural.The traditional off-white gi conforms to that, the modern bleached one is borderline; the color still exists naturally in for example, fresh white snow, but it isn't quite natural anymore for the fabric. The blue gi violates the principle of wabi, being completely unnatural. Kano's own first 'gi' was not white either, it was natural.

Many seniour Judoka do not necessarily have a huge problem with the blue judogi for international competition, although many would prefer that the IJF had not bothered with it. The reasoning why Kano Sensei chose a simple white gi is just as valid today, as it was in his. It does remove distinction and distraction in the dojo. With just a plain old white judogi, we are all the same, just judoka training in the way.