As mo is the most important garment in juni-hitoe (traditional multi-layer court costume, literally, twelve-layered ceremonial kimono) layered garment of the Heian period, and people had to wear mo when they served those who were elder or at a higher rank than themselves.
裳は平安時代十二単の中で一番ポイントとなる物であり、自分より身分の高い人、或いは目上の者の前に出る場合は裳は必ず着用せねばならなかった。