Well, as you have noticed by now... it varies.
Just the same as how the levels in Aikido, as well as the contents of the test, vary from dojo to dojo.
For our dojo it currently stands as this:
- 6 kyu ranks for adults before testing for Shodan.
A lot of places, both stateside and in western Europe have 5 kyus.
[How this actually translates for someone moving from 6 to 5 kyus is of interest, due to the extra time put in as well as the test being a bit more comprehensive as well - though I will make no assumptions.]
- Our dojo does go by the color belt system, which seems that is more commonly found in places with 6 kyu ranks. [again, this does not mean or imply the testing criteria is the same... eventually it all evens out...]
- When I first started, I believe that Hakama was permitted to be worn at 3rd kyu, however that for sure has been changed by our Technical Leader to be exclusive to 2nd kyu [blue belt] and above.
[though it is optional in our dojo for 2nd & 1st kyu to wear them...]
I would tend to agree that beginners would be better off not wearing the hakama - in seminars its a lot easier to quickly assess where someone 'should' be at this way... thus why I like colored belts.
note: yes, color belts do not necessarily mean peoples skills are on the same level - even within a dojo, but its not a bad indicator to get started.
So when you see someone with a Hakama you are pretty sure you will get someone who knows what they are doing. [people can start teaching at 2nd kyu here... while it is rare, one police officer [2nd kyu] from our dojo teaches in the neighboring city - smaller city, etc.]