Like many other things in the Heian era, aristocratic clothing was influenced by China, in particular a Chinese tendency in the later Tang and Sung dynasties toward layered clothing. The formal clothing of aristocratic Heian women, the karaginumo (Chinese coat skirt), was not a simple copy of Chinese designs, but, instead, a garment that elaborated on during the relative isolation of the Heian era to produce something Chinese-influenced but still very much Japanese in flavor.
The karaginumo is often referred to as the junihitoe, an expression that translates as "twelve unlined robes." Although this does accurately reflect the layered nature of the the clothing, it's a bit of a misnomer in that there was no special fixation on twelve exact layers or even unlined clothing. The tendency to refer to the karaginumo as junihitoe stems from an over-extrapolation based off a single popular literary source from the period. The actual number and nature of the layers would vary by season and occasion. In many cases, it would exceed twelve, though modern versions of the karaginumo, which are mostly only worn in ceremonial occasions by members of the imperial court, tend toward a small number, often five.
|Emperor (then Crown Prince) Akihito and Empress Michiko at their wedding in 1959.|
At the core of all these layers, aristocratic women wore a narrow-sleeved robe called the kosode. These were normally made of silk. The kosode would be tucked into a type of baggy ankle-length divided skirt-like affair called a hakama. There would be another, longer hakama worn over the first.
Over the above, were the actual layers, loose-fitting robes referred to as uchiki. These would be unlined during the summer and lined during colder seasons. Over the various uchiki, the proper lady would wear a half-coat and a train decorated with streamers. The sleeves of the robes were straight and extremely long. Each uchiki was smaller than the layer beneath it. This resulted in the layer edges being visible at the hem, sleeves, and neck.
Although most uchiki didn't include some of the extensive patterns seen in later-era kimono-wear, the individual uchiki were typically dyed in various solid colors except for the two top layers. The top layers would normally be brocaded silk and could include patterns.
Now, with all these layers, long hakama, and what not, one might think this would have a serious impact on mobility. Indeed, the elaborate court clothing of the Heian-era aristocratic woman didn't make movement easy at all. It wasn't unusual for intra-room movement to be confined to knee-based movement. Unsurprisingly, these women required servants/ladies-in-waiting to aid them in getting dressed.
The crippling of their movement wasn't a particular disadvantage to these women under normal social circumstances. For the most part, their day was spent sitting in a limited number of locations.
Of course, the huge number of layers obliterated any real hint of body profile. For all the Heian-era obsession with beauty, various indications from period literature and diaries at the time seem to suggest that the Heian-era aristocracy didn't actually find the actual body beautiful.