
InJapanese architecture, theomoya (母屋) is the core of a building. Originally, the central part of a residential building was calledomoya. After the introduction ofBuddhism to Japan in the 6th century,moya has been used to denote the sacred central area of a temple building. It is generally surrounded by aisle like areas calledhisashi.[1] In temples constructed in the hip-and-gable style (irimoya-zukuri), the gabled part usually covers themoya while the hipped part covers the aisles.[2]

The drawing shows the floor plan of a typical Zen mainbutsuden such as the one in the photo above atEnkaku-ji inKamakura. The core of the building (moya) is 3 x 3ken wide and is surrounded on four sides by a 1-ken widehisashi, bringing the external dimensions of the edifice to a total of 5 x 5 ken.[3] Because thehisashi is covered by a pent roof of its own, thebutsuden seems to have two stories, but in fact has only one.
This decorative pent roof which does not correspond to an internal vertical division is calledmokoshi (裳階・裳層,also pronouncedshōkai), literally "skirt story" or "cuff story".
The same structure can be found in atahōtō with the same effect: the structure seems to have a second story, but in fact it doesn't.[4]