Aikido is one of a few martial arts where practitioners wear a hakama. When O Sensei taught Aikido, he required students to wear hakama during practice. Many of his students didn’t have a lot of money and would take old futon covers, dye them blue/black and convince someone to sew the salvaged fabric into a hakama. The story is that over time the dye would wear away and the original futon prints would start to show through.
Since that time, Aikido dojos have adopted various policies on wearing the hakama ranging from “everybody wears them”, through “only the head instructor wears one”. The Aikido Olympia approach is that people shodan (first dan blackbelt) and above wear the hakama. Our rationale is that it’s easier to help students work out their footwork and movement with techniques when a bolt of black fabric is not hiding their feet and legs.
Finally, the folding a hakama. The pleats and the long straps of these pants make them difficult to maintain, and difficult to fold into a portable package. There is a practical reason you’ll see yudansha folding their hakama on the edge of the mat after practice- they don’t want to iron it and if they can fold it in a way that protects the pleats, they don’t have to. You might also notice that senior students will ask to fold the instructor’s hakama. This demonstrates respect, helps people learn how to fold the hakama, and creates a game where everyone is demonstrating how they’re still applying martial awareness after the class has ended.