The first half of the Heian period was an era of straight swords, during which the ornamental sword style which is the form of highest-rank sword mountings was established and adopted when attending ceremonies wearing sokutai (traditional ceremonial court dress), but such style was only allowed to the highest-ranked Kugyo (the top court officials).
平安時代も前半はまだ直刀の時代で、この時期に最高位の刀剣外装である飾剣様式が完成し、束帯姿で儀式に参列する時などに佩用されたが、上級の公卿にしか使用は許されないものであった。