The history of the development of the kimono can be traced to the Nara period (710-784). This was a time of great influence by T'ang dynasty China, consequently, the long, flowing Chinese robe became the model for the early kimono prototype. During the Heian period (794-1185)Japan closed its doors to China and her direct influences and, as a result, the first distinctive Japanese art forms began to emerge. The kimono developed from the small-sleeved, white undergarment worn next to a woman's skin called a kosode. On top of that was worn several layers of colorful over-jackets with wide, trailing sleeves, as well as hakama, a type of wide-legged split trousers that tied at the waist. The ultimate manifestation of this period of dress was the junihitoe, or twelve-layered ceremonial robe, which was considered proper attire for ladies of nobility. Over the centuries, the number of robe layers began to diminish and the simple kosode undergarment was transformed into outerwear, which then began to be embellished with color and pattern. Eventually, the trousers were no longer worn and a narrow sash was adopted to secure the robe in place. By the the Edo period (1600-1868), the sash had grown wider and more elaborate, establishing the basic kimono and obi that we see today.