Also called *hakkaku endō 八角円堂. An octagonal hall. There are six extant, five of which are designated as national treasures and the other as an important cultural property. All are small structures. Five are erected on stone podii with access by steps on one two, three, or four sides. The one at Kōryūji Keikyūin Hondō 広隆寺桂宮院本堂 (Kamakura period) has simple plank flooring under which is a white, plaster-covered, turtle-back-shaped mound called *kamebara 亀腹. The oldest octagonal hall is the Hōryūji Tōin *Yumedono 法隆寺東院夢殿 in Nara. Although the original building was relatively simple and well proportioned, it underwent considerable repair and remodeling in 1230. The only other octagonal hall remaining from the Nara period is the one at Eizanji 栄山寺 (757-64). Two clearly dated octagonal halls remain from the 13th century. They are Kōfukuji *Hokuendō 興福寺北円堂 (1210) in Nara, and Hōryūji *Saiendō 西円堂 (1250). The beams and pillars in octagonal halls were also made octagonal in cross section. These buildings were erected by patrons dedicated to a specific Buddhist deity or saint to whom they wished to pay homage or as a way to gain special merit in the hereafter.
