The practice of Aikido is a close sport, and can be a dangerous one if protocol is not followed. The dojo also thrives and survives on a spirit of cooperation. Therefore it is important that every Aikidoka understand and follow the rules of dojo etiquette.
Generally speaking, personal growth should be the focus of one's Aikido practice, and not the gaining of rank. However, a ranking system does exist in Aikido. The following explains KSU Aikikai's interpretation of the ranking system.
Students start out unranked. After attending 60 days of classes, a student may test for his or her first rank: 5th kyu (prounounced cue). Once a student has tested successfully, the practice count begins over. Upon 80 more days of practice, the student may test for 4th kyu, and so on. Kyu ranks continue up to 1st kyu. Kyu ranks are tested within the dojo by Sensei Dan, and at his discretion.
Dan (pronounced "dahn") rankings are the next step after kyu rankings, and count upward from one. A shodan (first dan) is what most martial arts call a "first degree black belt." Progressing in dan rankings typically takes years of practice, as well as going to multiple outside seminars. It is said that once one achieves shodan, then an Aikidoist finally becomes a serious student. Students testing for dan rank test at seminars with shidoin.
All kyu ranks at KSU Aikikai wear white belts, and all Dan ranks wear black. Hakama are typically worn starting at 2nd kyu.
While it is tempting to think that simply putting in the appropriate amount of time qualifies one to test, testing is always up to the discretion of one's Sensei. Testing is not simply about completed hours, but is also about attitude and ability.