Chofuku is the clothes that government officials wore from the Aska period to the Heian period when they came to work at the Imperial Court.
According to wafuku (traditional Japanese clothes) glossary, there were two types of ho (robe or jacket): hoeki no ho (robe with sides being stitched) for civil officers and ketteki no ho (robe without sides being stitched) for military officers.
As the system of chofuku was established under the influence of the Tang dynasty, it is estimated that chofuku looked like the ones in China for some time. Later, under the influence of the Kokufu Bunka (Japan's original national culture), chofuku changed into ikan sokutai (traditional ceremonial court dress) and noshi (everyday clothes for nobles).
Though chofuku had been established by the period of the Emperor Kotoku, it was temporarily abolished at the period of the Emperor Tenmu. During the period of the Emperor Monmu, with the establishment of Taihoryo (Taiho Code), the system of raifuku (formal court attire), chofuku and seifuku (uniform) was introduced.
According to the stipulation by 'ebukuryo' (The garment code) of "Yoro ritsuryo code (the code promulgated in the Yoro period)," the ho (robe) of civil officers was called 'e (衣)' while ho of military officers was called 'ou (襖),' which seems to have been ketteki no ho.
Ikai (court rank) and the color and construction of chofuku
According to the ritsuryo code, from Ippon Shinno (the first-ranked Imperial Prince) down to subjects the tojiki (the color corresponding to one's official rank) of chofuku was the same as that of raifuku (formal attire). Imperial Prince's color was deep purple and the color for subjects from from nii (second rank) down to goi (fifth rank) was pale purple. For subjects, it was stipulated that the color of ichii (first rank) was deep purple, nii and sanmi (second and third rank) pale purple, shii (fourth rank) deep scarlet, goi (fifth rank) pale scarlet, rokui (sixth rank) deep green, shichii (seventh rank) pale green, hachii (eighth rank) dark blue and shoi (initial rank) azure blue, respectively.
The officials of the fifth rank or higher wore kuri no usuhara skullcap, geshaku (ivory tablet), sash decorated with gold and silver, white hakama (a formal divided and pleated skirt for men) and uhiri (black leather shoes). And the officials of the sixth rank or lower wore kuri no katori skullcap, mokushaku (wooden tablet), black sash, white hakama, shirotozu (white tabi, or socks) and uhiri.
In order to fasten the ho (the robe), sekitai (leather belt) was used, which was the same as the one used for sokutai (traditional ceremonial court dress) later. The stone attached to the sekitai was found at the ruins of government offices around Japan.
The transition of the time
Over time chofuku gradually changed into sokutai, and with the change, chofuku came to be regarded as more important than before changing its role from the normal working clothes for government officials to the ceremonial dress and formal attire.
In January, 774, the color of chofuku for the second-rank Ministers was decided as medium purple, and in July, 806 the color for shichii (seventh rank) was changed to deep green, the same as rokui (sixth rank), and the color for shoi (initial rank) was changed to dark blue, the same as hachii (eighth rank), and in September, 810 the dress color for Shoo (prince who didn't receive any proclamation to be an Imperial Prince) was changed from pale purple to medium purple and the color for the second rank Ministers was changed from medium purple to deep purple and the color for nii and sanmi (second and third ranks) was changed from the pale purple to medium purple. With the changing method of dyeing, the Kanko era and later the three colors were decided, that is, for shii (forth-rank) or higher as black, the gou (fifth-rank) as dark red and rokui (sixth-rank) or lower as hanada (light blue).