The most important thing in your aikido practice should be your personal development, and of your colleagues, not to take exams. Try to enjoy the process and treat exams as ways of gauging your skills and your progress, rather than aims in themselves.
We adopt the Kyu-Dan system: There are five kyu ranks (white belt) followed by eight Dan ranks (black belt).
For each rank there is a minimum number of practice days that are prerequisite for testing. The number of days are counted after the last exam. Remember you might need more than the minimum to be ready to test, so don’t rush. Your instructor will define when he thinks you are ready and agree a date for the exam. It is important you familiarize yourself with the names of the attacks and of the techniques.