The seven pleats in the hakama represent Seven Virtues of Budo [the Martial Way] and are described in the following article by Mitsugi Saotome Sensei from his book The Principles of Aikido.

The Hakama and It's Meaning

     When I was uchi deshi [live-in student] to O Sensei, everyone was required to wear a hakama for practice, beginning with the first time they stepped on the mat. There were no restrictions on the type of hakama you could wear then, so the dojo was a very colorful place. One saw hakama of all sorts, all colors and all qualities, from kendo [the Way of the Sword] hakama, to the striped hakama used in Japanese dance, to the costly silk hakama called sendai-hira. I imagine that some beginning student caught the devil for borrowing his grandfather's expensive hakama, meant to be worn only for special occasions and ceremonies, and wearing out its knees in suwariwaza [techniques done from kneeling] practice.

     I vividly remember the day that I forgot my hakama. I was preparing to step on the mat for practice, wearing only my dogi, when O Sensei stopped me.

     "Where is your hakama?" he demanded sternly. "What makes you think you can receive your teacher's instruction wearing nothing but your underwear? Have you no sense of propriety? You are obviously lacking the attitude and the etiquette necessary in one who pursues budo training. Go sit on the side and watch class!"

     This was only the first of many scoldings I was to receive from O Sensei. However, my ignorance on this occasion prompted O Sensei to lecture his uchi deshi after class on the meaning of the hakama. He told us that the hakama was traditional garb for kobudo [traditional martial ways]  students and asked if any of us knew the reason for the seven pleats in the hakama.

     "They symbolize the seven virtues of budo," O Sensei said. "These are jin (benevolence), gi (honor or justice), rei (courtesy and etiquette), chi (wisdom, intelligence), shin (sincerity), chu (loyalty), and koh (piety). We find these qualities in the distinguished samurai [warriors] of the past. The hakama prompts us to reflect on the nature of true bushido [the Warrior's Code]. Wearing it symbolizes traditions that have been passed down to us from generation to generation. Aikido is born of the bushido spirit of Japan, and in our practice we must strive to polish the seven traditional virtues."

     Currently, most Aikido dojo do not follow O Sensei's strict policy about wearing the hakama. Its meaning has degenerated for a symbol of traditional virtue to that of a status symbol for yudansha [black belt holders]. I have traveled to many dojo in many nations. In many of the places where only the yudansha wear hakamas, the yudansha have lost their humility. They think of the hakama as a prize for display, as the visible symbol of their superiority. This type of attitude makes the ceremony of bowing to O Sensei, with which we begin and end each class, a mockery of his memory and his art.

     Worse still, in some dojo, women of kyu [undergraduate] rank (and only the women) are required to wear hakama, supposedly to preserve their modesty. to me this is insulting and discriminatory to women aikidoka [aikido practitioners]. It is also insulting to male aikidoka, for it assumes a low-mindedness on their part that has no place on the Aikido mat. 

     To see the hakama put to such petty use saddens me. It may seem a trivial issue to some people, but I remember very well the great importance that O Sensei placed on wearing hakama. I cannot dismiss the significance of this garment, and no one, I think, can dispute the great value of the virtues it symbolizes. In my dojo and its associated schools I encourage all students to wear hakama regardless of their rank or grade. (I do not require it before they have achieved their first grading, since beginners in the United States do not generally have Japanese grandfathers whose hakama they can borrow.) I feel that wearing the hakama and knowing its meaning, helps students to be aware of the spirit of O Sensei and keep alive his vision. 

     If we can allow the importance of the hakama to fade, perhaps we will begin to allow things fundamental to the spirit of Aikido to slip into oblivion as well. If, on the other hand, we are faithful to O Sensei's wishes regarding our practice dress, our spirits may be more faithful to the dream to which he dedicated his life.

NB: Italics added. Definitions of terms appear in brackets.