Policies governing rank promotions may vary, sometimes dramatically, from one aikido dojo or organization to another. According to the standard set by the International Aikido Federation (IAF) there are 6 ranks below black belt. These ranks are called kyu ranks. In the IAF, kyu ranks are not usually distinguished by colored belts. Other organizations (and some individual dojo) may use some system of colored belts to signify kyu ranks, however. There is a growing number of Aikido organizations and each has its own set of standards for ranking.
Eligibility for testing depends primarily (though not exclusively) upon accumulation of practice hours. Other relevant factors may include a trainee’s attitude with respect to others, regularity of attendance, and, in some organizations, contribution to the maintenance of the dojo or dissemination of Aikido.
Whatever the criteria for rank promotion, it is important to keep in mind that rank promotion does not necessarily translate into ability. The most important accomplishments in Aikido or any other martial art are not external assessments of progress, but rather the benefits of your training to yourself.