Hakama is a traditional Japanese wear which is used in graduation ceremony of a highschool and for budo sports such as kendo, and iaido. It can also be weared in Seijinshiki, the annual day of celebrating young people who have turned twenty.
Hakama cover the lower body and resemble a wide skirt. It is tied at the waist, and it's length is approximately to the ankes. Hakama is worn over kimono.
Divided (umanori) hakama allows horse-riding and undivided (gy?t? hakama) is more like a skirt. There is also third type of hakama, used by farmers or forest workers.
Hakama was a cloth of samurai. Since it didn't restrict the movement, it's very well functioning cloth in life of ancient warrior, who must have responded quickly to surprise enemy attack. Some also suggest that horse riding samurais benefitted from hakama in the same way as cowboys benefited from chaps, the leather trouser protectors.
Hakama can also be used in festivals "o matsuri".