While the vast majority of martial arts uses some form of belt system to show the advancement of a pupil to a higher level of knowledge and skill, they do not all use the exact same system.
Karate, which is the traditional and most practiced martial arts in Japan, uses a variety of colors to indicate what level the student has achieved.
The progression of the colors used in Karate can also differ depending on the style being taught. What people do not realize is that many martial arts have various sub genres within the discipline themselves such as Wado-Ryu and Goju-Ryu Karate.
The progression for Wado-Ryu Karate is as follows:
As you can see the levels are many and the training it takes to reach each subsequent level is difficult, and gets more complex as you get higher into the ranks.
Judo however uses a different color scheme than Karate and offers belts that are red to its most knowledgeable and experienced masters.
Here are the traditional progressions for Judo trainers:
After achieving a black belt in Judo, you must progress through a series of levels known as “Dans”. The first five “Dans” all stay at black but when you reach the sixth level, you then get a red and black belt until you reach the final level of tenth “Dan” which nets you a solid red belt and shows the world that you are a true master of the discipline.
Most other forms of martial arts use a very similar system to show where the student is in his progression with slight variations as mentioned above.
There are exceptions to this common rule however. In some forms of “Muay Thai” which is a martial art practiced in Thailand and surrounding areas, they traditionally use colored shorts rather than belts to signify the level achieved.