A style of shrine architecture characterized by a structure which from the side-view gives the impression of two separate buildings with parallel ridges placed one behind the other, each with its own gable roof *kirizuma yane 切妻屋根. A rain gutter *toi 樋, joins the eaves of the two roofs. The space that results between the two buildings is enclosed to form a 1-bay deep room *ai-no-ma 相の間. The width of this intermediate space varies from shrine to shrine as does the height of the floor. Generally, the rear building is 3 X 2 bays and the front one 3 X 1 bays. The entrances are placed in the central bays of each building and the step canopy *kōhai 向拝, is extended over the stairs of the front building. The rear building is the principal sanctuary and is usually called *honden 本殿 although it may also be called naiden 内殿, *naijin 内陣 or *shōden 正殿. The front building is called *haiden 拝殿, *gejin 外陣, or geden 外殿. The twin halls *narabidō 双堂 may have been associated with Buddhist architecture which had a *shōdō 正堂 and worship hall *raidō 礼堂, at the back and front of the building respectively. However, shrine halls of this type are not open for use even to ordinary priests as both are occupied only by the deity, kami 神. At the Usa Hachimangū 宇佐八幡宮, Ōita Prefecture and Iwashimizu Hachimangū 石清水八幡宮, Kyoto, the front area has a chair and the rear area has a raised curtained dais, michō 御帳 or chōdai 帖台. This furniture is of Heian vintage. Daises were used in the bedroom and chairs were used in the room used during the daytime. It is presumed by some scholars that since such expressions as dedono 出殿 (departure hall) referred to the front area in the twin hall type shrine the kami could change easily from the rear to front hall and return at will. The use of latticed-mounted board doors *shitomido 蔀戸, on the front, double-leaf doors *tsumado 妻戸 on the gable side at each end of the ai-no-ma, and simple boat-shaped brackets *funahijiki 舟肘木, in hachiman style shrine buildings, strongly suggests a close relationship with the Heian period aristocratic style dwellings *shinden-zukuri 寝殿造. Another possible source for the hachiman-zukuri might have been drawn from the parallel double ridges known to have existed in early palace architecture. The earliest extant buildings in this style date from the Edo period, and only five survive. Examples: Usa Hachimangū Honden and Haiden; Iwashimizu Hachimangū Honden and Haiden ; Ima Hachimangū 今八幡宮 Honden and Haiden, Yamaguchi Prefecture.