The Twelve Level Cap and Rank System (冠位十二階, Kan'i Jūnikai), established in 603, was the first of what would be several similar cap and rank systems established during the Asuka period of Japanese history.
[1] It was adapted from similar systems that were already in place in Sui dynasty China, Paekche and Goguryeo.
The ranks in the twelve level cap and rank system consisted of the greater and the lesser of each of the six Confucian virtues: virtue (徳, toku), benevolence (仁, jin), propriety (禮, rei), sincerity (信, shin), justice (義, gi) and knowledge (智, chi).
One of the more well known examples of promotion within the cap and rank system is that of Ono no Imoko.
The following table lists the various ranks and the colors that were believed to have been assigned to each one.