The minimum time requirements for advancement are set by Honbu Dojo in Japan, yet these have little to do with the actual requirements that must be met. The dan System consist of nine dans, or levels, divided into three groups. In other works 1-3 dans is the beginners level. 4-6 is intermediate, and 7-9 is the level of mastery. The beginning level (Triangle) is physical, the intermediate level (Circle) is mental and the advanced level (Square) is spiritual. Understanding, of course, that the various aspects of the training will not always proceed in a systematic manner, nevertheless this order shows the criterion for advancement of rank in the Shobu system.
Physical training refers to Renshu, learning through physical repetition and conditioning. The most advanced training is already encountered here, yet not grasped. Mental training indicates bringing deliberate concentration into the practice and focusing on the manifestation of aiki principle in technique. Spiritual means intuitive understanding. At this stage ones intent is manifest immediately as principle and understood as the root of all movement and power.
Shodan (first level)
At the Shodan level the student is required to demonstrate a fundamental understanding of all basic technique including both barehanded and weapons training.
Nidan (second level)
At the Nidan level basic technique must be demonstrated with fluidity and greater precision. Some more advanced weapons kata are also included.
Sandan (third level)
Sandan is the final level of the physical category and the student must demonstrate Kokyu Ryoku, the power of kokyu. This requires a grasp of ki extension or expanding one’s ki in all directions from center in all basic techniques. Sandan is seen as the most physically powerful time.
Yondan (fourth level)
Yondan indicates the ability to overcome physical power with technique. All dependency on physical tightness must be surrendered, yet in order to do so effectively, the kokyu Ryoku of Sandan must already be firmly established. It should be understood that all levels are based upon those that precede them.
Even perfect technique will be ineffective without kokyu Ryoku, the expansion of ki from one point.
Godan (fifth level)
This is the pivot point between the beginner (first level) and the sage (ninth level). It is the realization of one point and intent, which resides in one point, as the origin and control center of all movement. Traditionally this is the first level of a qualified teacher.
Rokudan (sixth level)
At Rokudan aiki principle is manifest in its completed spiral form and controlled by intent. The realization of mind over matter has become clear. The student has become rounded and gentle: there is no more haughtiness or arrogance. At this level the student should be able to continually progress even without the guidance of a teacher. This requires a good deal of humility and self-reflection.
Nanadan (seventh level)
Nanadan is the first level called spiritual. There is no more emphasis on technique although it may still be used as a tool for research and training. Rather the emphasis is on merging your own movement with the flow of nature; remaining connected with your partner, yet completely independent. This level is also referred to in Japanese as the “Shihan” or mastery level, yet, as far as spiritual, or intuitive mastery, it is still the first step.
Hachidan (eighth level)
Hachidan is a complete master teacher; one who can lead the world towards transformation, peace, and harmony. If there is still conflict in one’s heart this level has not yet been achieved. Hachidan should be an example of a sage or great teacher.
Kudan (ninth level)
This is the level of complete freedom and enlightenment; it is no longer dependent on physical training. At Kudan there is no more technique. The person themselves is an embodiment of Aiki. Aikido is not for oneself but for others. It is for the purpose of helping others and creating a better world. This is the highest level. There is no ten dan in the original system as that would indicate going beyond the relative world of nature.