According to "Hososhiyo-sho" (a legal book compiled by the Sakanoue clan between the end of the Heian period and the early Kamakura period), which described rules and regulations on dismounting a horse depending on his court rank based on the Ritsuryo Law system (an ancient administrative law system in Japan), a person of the third court rank or the lower had to dismount his horse when he met any imperial prince on the road, and even any lower-ranked or younger person without Ikai (a court rank) had to follow the same manner toward the nobilities and the elderly.
「法曹至要抄」には、三位以下の者が路上で親王に会えば下馬するのをはじめとして、位階に応じてそれぞれ下馬の令制を載せ、有位者でない場合も賤者、少者は貴人、老人に対して同様にすべきであった。