The Hakama was originally used in Japan by horseback riders to protect their legs from brush, brambles, etc. It was also used for formal occasions.
Today the Hakama is worn outside of Japan mostly by Aikido, Iaido, Aiki-Jujutsu and a few other martial arts groups. The Hakama is worn in Iaido both for symbolism and training. There is the tradition of the Samurai, from which our Iaido instruction and concepts evolved. There is also the idea of awareness. In Iaido, the Hakama is a training tool to improve and develop one’s technique, demanding greater awareness of foot movement in particular.
In a Dojo setting where Hakama are not normally worn, the wearing of the Hakama allows the junior student to identify the instructor instantly. It helps to define boundaries within the Dojo environment by showing the most senior persons and allowing all to be able to instantly know who they are. The Hakama becomes a symbol to those who enter the Dojo – a symbol that the instructor must be mindful to preserve. Putting on the Hakama can make one the center of attention. Be sure you are ready for that attention at all times.
In an Iaido setting, the Hakama is worn by all students regardless of rank and is useful in the proper wearing of the sword on the hip. The concealment of the foot movements by a swordsman is another reason why such garments might have been worn and this behavior is replicated in the Dojo as part of our physical and historical training.
The Hakama is somewhat bulky to wear and an especially long style was originally worn for ceremonial reasons. Wearing this Hakama would restrict your movements and would usually be worn in the presence of someone of higher rank, such as your liege or lord. While wearing the Hakama, it would be difficult to attack this person or to defend yourself from their attack. Thus, the wearing of the Hakama is also a form of trust and respect to others.
The Hakama also helped to symbolize the life of the samurai and how to live that life. In the front of the Hakama are five pleats. Each pleat represented five relationships (Go Rin) that were considered dominant in the life of the Samurai. The Samurai was required to classify all of their relationships and to place them in one of these five. It was felt that if they could not place the relationship in its proper place, then it was required that the relationship be alter or be discarded. The relationships have a hierarchy of importance and they are: Lord/Vassal (A Cause or Higher self/Inner Spirit); Father/Son (Teacher/Student); Husband/Wife; Young/Old; Friends, in that order of importance. The Samurai was required to ensure that a lower level relationship did not interfere with a higher level one. If this were to occur, you placed your life under stress and difficulty. It was essential to ensure that nothing interfere with higher obligation or duty and thus the five relationships were categorized.
Finally, there are the two back pleats called Chukio Ichi Go (Two become One – Humility/Reverence plus Loyalty) The back pleats represent the driving force of the Samurai, making them continue onward even when all else was against them. Loyalty to one’s lord, master, family, teachers, and friends was more important that one’s life itself. Humility and Reverence in all of these relationships was equally important, far more so than just fighting ability. Thus, these attributes remain behind the Samurai, to push them forward, to develop and grow.