In 820, it was decided by Imperial edict issued by the Emperor Saga (Nihonki ryaku (The Abbreviated History of Japan) and Ononomiya Annual Ceremonies), and according to the Shosoin documents, it was conjectured that the clothing for the Emperor was white and had no embroidery (although it was worn at the eye-opening ceremony of the Great Buddha).
これは弘仁11年に嵯峨天皇の詔で決められたものらしく(日本紀略・小野宮年中行事)、奈良時代には白で刺繍のないものであったらしいことが正倉院文書から推定されている(ただし大仏開眼会での所用品)。