Hakama are worn over a kimono. There are four straps, a long one on either side of the front of the garment, and a short one on either side of the rear. The rear of the garment has a rigid board-like section and a toggle which is tucked into the rear of the obi, and helps to keep the hakama in place.
Hakama were originally worn by samurai, and had the same function as chaps, the leather trouser protectors worn by cowboys in the west, that is, to protect the clothing.
Hakama have seven deep pleats, two on the back and five on the front. The pleats are supposed to represent the virtues considered essential by the samurai. Many martial artists continue this tradition, but different sources give different meaning to these pleats.
The most formal type of hakama are made of stiff, striped silk, usually black and white, or black and grey. These are worn with black montsuki kimono (kimono with one, three, or five family crests on the back, chest, and shoulders), white tabi (divided-toe socks), white under-kimono and woven straw sandals of various types. In colder weather a montsuki haori (long jacket) with a white haori-himo (haori-fastener) completes the outfit.
Hakama can be worn with any type of kimono except yukata (light cotton summer kimono generally worn for relaxing, for sleeping, or at festivals or summer outings). While striped hakama are usually worn with formal kimono, stripes in colours other than black, grey and white may be worn with less formal wear. Solid and gradated colours are also common. A hakama makes any outfit a little more formal.
While hakama used to be a required part of men's wear, nowadays men usually wear hakama only on extremely formal occasions, and at tea ceremonies, weddings, and funerals. Hakama are also regularly worn by practitioners of a variety of martial arts, such as kendo, aikido, kyudo, et cetera. It is said that the flowing fabric of the hakama can disguise the movements of the warrior giving him an advantage in combat.
Sumo wrestlers, who do not wear hakama in the context of their sport, are, however, required to wear traditional Japanese dress whenever they appear in public. As hakama are one of the most important parts of traditional male formal dress, sumo wrestlers are often seen wearing hakama when attending appropriately formal functions.
There are many ways for men to tie hakama. First, the obi is tied in a special knot (an "under-hakama knot") at the rear; men start with the front section, bringing the ties around the back and crossing them over the top of the knot of the obi. The ties are brought to the front and crossed below the waist, then tied at the back, under the knot of the obi. The toggle is then tucked behind the obi, and the rear ties are brought to the front and tied in a variety of ways. The most formal method results in a knot that resembles two bow-ties in a cross shape.
Women's hakama differ from men's in a variety of ways, most notably fabric design and method of tying.
While men's hakama can be worn on both formal and informal occasions, women rarely wear hakama except at graduation ceremonies, though this is by no means a rule. While formal men's hakama are made of striped fabric, women's hakama tend to be of single-colour or gradated fabric.
Women wear hakama at the true waist, while men wear them slightly below. The method of tying the straps is also different, with women's hakama being tied in a more simple knot.
Women also wear hakama as part of their martial arts uniforms, but only very rarely at tea ceremony.
Scarlet hakama are characteristic of miko, or female Shinto shrine attendants. Red hakama could be considered the Shinto equivalent of a Christian Nun's habit. Monks also wear a garment that bears a small resemblance to hakama, though as it is shorter, tied differently, and made of lighter, usually orange silk, it more closely resembles an apron. Shinto shrine workers wear white kimono and white hakama.