The ranking and grading:
Judo rank is generally not of primary importance among those who participate in tournaments. Modern Judo is primarily practised as a sport, so there tends to be more emphasis on tournament records than on rank. Since rank does not totally determine competitive performance, and since tournaments are not structured by rank (except at the lowest novice levels), it is not uncommon to see lower-ranked competitors defeat higher-ranked opponents.
An active competitor may not pursue high ranks, preferring to focus on preparation for competition; for example, a silver medal was won by an brown belt female competitor, Lorena Pierce, in the -70 kg category at the 2004 Paralympics. Apart from knowledge and ability, rank requirements typically include a minimum age. Therefore, it is not uncommon to find teenage competitors at national-level competition who have been practicing Judo for ten years who can beat adult practitioners, but who are only purple or brown belts due to being too young to qualify. Once an individual attains the level of a dan rank, further promotions can be granted for a variety of reasons including skill level, competition performance and/or contributions to Judo such as teaching and volunteering time. Meaning that though it often does mean that you are better depending on your rank, it does not mean that you of a lower rank. Cannot best them, for it can occur.
Practioners of Judo are ranked according to skill and knowledge of Judo, and their rank is reflected by their belt color. There are two divisions of rank: below-black-belt-level "grades," (kyū) and black-belt-level "degrees." This ranking system was introduced into the martial arts by Kano and has since been widely adopted by modern martial arts. As initially designed, there were six student grades ranked in descending numerical order. There are ordinarily ten "degree" (dan) ranks, which are ranked in ascending numerical order, though in principle there is no limit to the number of dan ranks.
The tenth degree black belt and those above it have no formal requirements. The president of the Kodokan, currently Kano Jigoro's grandson Yukimitsu Kano (Kano Yukimitsu), decides on individuals for promotion. Only fifteen individuals have been promoted to this rank by the Kodokan. On January 6, 2006, three individuals were promoted to 10th dan simultaneously: Toshiro Daigo, Ichiro Abe, and Yoshimi Osawa. This is the most ever at the same time, and the first in 22 years. No one has ever been promoted to a rank higher than 10th dan. However in theory the Judo rank system is not limited to just ten degrees of black belt. The original English language copy (1955) of Illustrated Kodokan Judo, by Jigoro Kano, says: "There is no limit...on the grade one can receive." This means that if one does reach a stage that is above 10th dan, then there is no reason why he/she should not be promoted to the 11th dan. However, since there has never been any promotion to a rank above the 10th dan, the Kodokan Judo promotion system effectively has only 10 dans. So far there have only been 15 10th dans awarded by the Kodokan in the history of Judo.
Although dan ranks tend to be consistent between national organisations there is more variation in the 'kyū' (grades,) with some countries having more 'grades.' Although initially kyū belt colours were uniformly white, today a variety of colours are used.
America
In America only senior players (adults, usually those age 16 and over) are allowed to earn dan levels, signified by wearing a black belt. The USJF and USJA recognise dan grades awarded by the other organization. Advanced 'grade' levels can be earned by both seniors and juniors (children under the age of about 16) and are signified by wearing belts of various colours other than black. The order of belt colours can vary from dojo to dojo, depending on the dojo's organizational affiliation. At the bottom is a table with the 12th to 1st kyū classes.
Seniors
For senior players, both the United States Judo Federation (USJF) and The United States Judo Association (USJA) specify four belt colours for the six 'grades,' as listed in the table. The USJA also specifies wearing a patch specifying the practitioner's level. This is true for both 'grade' and dan levels. It is also known that only seniors are able to qualify for the 'dan' classes for they must go through the 'kyū' classes first before they may go onto 'dan.'
Juniors
The USJF Juniors ranking system specifies ranks to 11th kyū. The USJA Juniors ranking system specifies twelve levels of rank kyū, beginning with 'Junior 1st Degree' and ending with 'Junior 12th Degree.' As with the senior practitioners, the USJA specifies that juniors wear a patch specifying their rank.
Here is a table of the 'Kyū' classes and belt colors for Seniors and Juniors of both the USJF and USJA standards:
| Japanese kyū names | USJF Senior |
USJF Junior |
USJA Senior |
USJA Junior |
USJA Junior level names |
| Jūnikyū |  |
Junior 12th class | |||
| Jūichikyū | |
 |
Junior 11th class | ||
| Jūkyū |  |
 |
Junior 10th class | ||
| Kūkyū | |
|
Junior 9th class | ||
| Hachikyū |  |
 |
Junior 8th class | ||
| Nanakyū | |
|
Junior 7th class | ||
| Rokkyū | |
 |
|
 |
Junior 6th class |
| Gokyū | |
|
|
|
Junior 5th class |
| Yonkyū | |
 |
|
 |
Junior 4th class |
| Sankyū |  |
|
|
|
Junior 3rd class |
| Nikyū | |
 |
|
|
Junior 2nd class |
| Ikkyū | |
|
|
|
Junior 1st class |
Here is a table of the 'Dan' classes that are in Judo. Though these are all black belt levels, this table also features the 'optional' wear for that same class. This is only the USJA standard:
| Japanese dan names | Belt Color | Optional Belt Color |
| Shodan |  |
|
| Niddan | |
|
| Sandan | |
|
| Yodan | |
|
| Godan | |
 |
| Rokudan | |
|
| Shichidan | |
 |
| Hachidan | |
|
| Kudan | |
 |
| Judan | |
|