Kumihimo - pronounced Koo-me-HEE-mo - as least as far as I've heard - is the Japanese form of braiding. Cords (round) and ribbons (flat) can be braided. According to Wikipedia:
Kumihimo cord was first created by a form of finger-loop braiding. Later tools such as the Marudai and the Takadai were employed to make more complex braids in shorter time. The most prominent historical use of the cords was by samurai as both a functional and decorative way to lace their armour. Kumihimo cords are now used deocarative as ties on jackets, and obijimes, which are used for tying on an obi (kimono sash).
The kumihimo disk has evolved as an inexpensive and portable replacement for the Marudai - which is an open ring on legs, usually made of wood, and about this size of a small stool. It uses dangling spools to create tension on the lines. The disks use the tension created by the notches, but spools to keep your cords tidy and organized and untangled are still very functional and useful.
We have findings that work nicely for Kumihimo, but could be used just as well for Viking Knit or beaded tubes.
As for the cord to use, we recommend starting with the Satin cords, which come in different sizes.