All traditional fabric is a narrow loom-width of about 14" and traditionally hand-woven. A kimono takes about 12.5 yds of this narrow fabric, and only enough silk is woven for one kimono at a time. Therefore, each one is very nearly unique. (An exception would be for a dance group who would wear matching ensembles.)
Since the 1970's, machine-woven silk, rayon, and polyester have become more common. All kimono, in fact, all traditional Japanese garments are hand-sewn. When they need cleaning, they are completely dismantled, washed, put on stretchers or boards to dry. Then they are re-sewn. They are carefully checked at this time for any worn areas. Collars might be turned, a worn area turned to the inside, the whole garment might be completely re-assembled. When you think how precious hand-woven, hand-dyed, hand-sewn garments are, this makes sense!
Probably everyone thinks they know what kimono are, but you might be very surprised at the range of fabrics and colors, and the differences in gender and age. The bright, colourful kimono with "swinging" or "butterfly" sleeves are for young, marriagable women. Adult women wear more somber colours and shorter sleeves. "Older" women, i.e. over 50, wear very dark colours and small patterns, if any. Men are limited to black or grey, solid or faint pinstripe for formal wear, and dark blue, grey, brown shades with very small patterns, if any, for less formal wear.
Very formal wear for adults of both sexes also includes the "mon" or crest in specified places on the kimono. Very formal wear will have five "mon": one on each side of the upper chest, one in the middle of the upper back, one on the back of each sleeve. Slightly less formal wear will have only three: the one in the middle of the back (it has a talismanic function) and the two in the front.
Very young girls wear the colourful, doll-like kimono, with very long sleeves, and frequently an attached sash. These are for special occasions such as New Years, Girls' Day, O-Bon, etc.
Before World War II, it was common for the kimono, or at least the sleeves to be lined, with red silk for girls and women. This was meant to be protective, especially against fire. This practice fell out of fashion after the war.
Under kimono and sleeping kimono might also be of red silk for the same reason. In the "old days", the underkimono might be of any color or pattern. Since the late 19th century and possibly due to Western influence, the under kimono for women, at least, is always white, giving the effect of a white blouse collar.
All kimono are based on a standard fabric width of about 14". They are made to fit very slender people by taking in large seam allowances. not by cutting the fabric. Most of them have a lot of "hidden" fabric inside. Men's kimono are shorter than women's because women's are "belted-up" to create an extra layer around the middle.
Sleeve length refers to the distance between the outstretched arm and the bottom of the sleeve, not the distance between the shoulder and the wrist opening. The length on the arm is always the same, i.e. the shoulder "drop" plus about 14". (Yes, Sumo wrestlers are a whole other problem.)
The obi is the sash that holds everything together. They vary from formal elaborate obi, as for young women or geisha, to the very simple, barely visible obi for men.
In addition to the actual obi, the obi-age or "scarf" is worn under the obi, just peeping out over the top, and the obi-jime is the cord that goes around the middle of the outside. There is a world of nuance and subtle meaning in the choice of obi fabrics and accessories as well as the way they are arranged. (See Liza Dalby's books in bibliography for comprehensive explanation).
HAORI are jackets for men or women. They are worn over the kimono and have kimono-type sleeves. They do not meet in front, but are fastened across the chest with ornamental ties. The ties for men's formal haori may come already tied and clip on to little loops on the jacket. The ties for women's jackets are either self-material or some pretty, coordinating woven braid.
As in the West, the most formal color is black, so most men's haori are black and are decorated only with the "mon" (see above). While haori are usually lined, frequently self-lined, formal summer haori may be unlined. As in putting on a suit jacket, adding a haori to a kimono makes it several degrees more formal.
Jackets also include women's KOTO or MICHIYUKI jackets. These are "double-breasted", fasten with snaps, and have a hidden pocket. They can range from hip length to ankle length and are meant as "dusters" to wear over the kimono when going out of doors. They are more frequently made from synthetics than kimono are.
HAKAMA (Japanese culottes)
Hakama come in two basic types: divided like culottes (also called "riding hakama"), or un-divided, like skirts. They may be worn by men or women depending on the occasion.
When the "small-sleeve kimono" began to be worn in the (roughly) 13th-14th century by women of the samurai class, the plain white silk garment was worn with red silk hakama. They are still worn by men, usually in a pinstriped silk, for formal occasions such as weddings (their own or others).
They are worn by women for specific occasions, such as graduating from college or musical performances. In both instances, they indicate serious and/or academic pursuits. For formal male dress, the hakama are worn over the kimono, and the haori is put on after that, so it hangs loose on the outside.
In samurai movies, you may have noticed that the haori is worn tucked inside the hakama. Hakama are also widely worn for martial arts by both sexes. This may be the purpose for which they are best known in the West. A woman may wear a haori or hakama, but never both together (except in movies!) For anyone pursuing an interest in Japanese costume beyond this admittedly sketchy introduction, please see accompanying bibliography.