It originated in Judo, and was based off of the coloring scheme used for members of the swim teams of Japanese high schools:
http://judoinfo.com/obi.htm
Before then, at least in the Japanese martial arts, you were either allowed to teach, or not.
Belt ranking can arguably be used to recognize skill level. You can pair those of similar ranks together for things like drilling or competition.
It can also arguably be used to get more money from students, if you charge them for each rank.
There are several good reasons. Motivation is one. Another is safety. As an instructor, belts help me sort students by ability and remind advanced students to take it easy when sparring lower ranks. Nobody benefits when a senior belt inflicts pain or injury, or just intimidates a beginner. The beginner gets discouraged and the advanced student isn't learning.
In class, we line up by rank, so each level can look forward to the next rank for ways to do things a little better. So, belts provide a framework for safe and productive group interaction and learning.
It is used for levels of ability among certain martial arts. A white belt is a beginner and would not be fighting on the same level as a black belt, who would be overseeing the training. Belts are given upon passing tests or when a sensei sees the student fit to practice more complicated techniques.
In other words, it's a way to recognize the strength of the student and helps them become better instead of having them constantly learning the same techniques over and over again without allowing them to improve.
Many of your styles and types of martial arts originally had no different colors of belts. Some like those Chinese styles and monks had different color robes which signified a level of enlightment and spiritualness. In Okinawan martial arts they had basically a white belt that over time would become darker from sweat, dirt, and blood as the practitioner continued to study and such belts would eventually turn brown and black from long years of training. This is where the custom of keeping your black-belt comes from and why in many of your traditional Okinawan and Japanese martial arts you will see black-belts that are old, faded and frayed is that it signifies a person who has studied and trained for a very long time.
The use of different color belts came into being in the 20s and 30s just prior to WW II and originally started in Japanese martial arts with Judo. It started because during that time frame there were a great many westerners in Japan some of whom had taken up studying Judo. For them it was very demotivating that as they rose in rank, skill, and ability there was no way of showing or denoting that and Jigoro Kano, the founder of Judo, instituted the belt color system for this purpose. Other styles and types of martial arts soon picked up on this practice and began to institute their own belt color system for this reason and to more clearly help denote one's rank and ability as well as to help keep students motivated to continue training and achieving higher ranks rather than the old custom of a belt just changing colors naturally and as it became aged and worn.
Its also an indication of skill level, there are other reasons as others have pointed out but for me ,will in my school i can tell the level the practitioner should be at by the ranking they hold.
It is a way to motivate students. Is like small certificates and when someone reaches the 4th Dan (in many organizations and styles) then he/she can open a school and start teaching others.
I want simple n understaining life partner...
More for govern cert if you teacher had problems in the past with his anger.
White, yellow, green, blue, red, black. Why do we have belt rank?
