in the space or for large in the earth-floored area. The style is most often found in Shiga and Fukui prefectures. 'Parallel crosses' are found in Shizuoka Prefecture and cover an area 5 metres by 10 metres. This system doubles up the 'cross' structure with two crosses and eight posts. The 'box' structure connects four or more post and beam units to create a box-like structure. It was devised in the Edo period and can be found in Toyama and Ishikawa prefectures. The 'interconnected box' can be found in Kyoto and Osaka. 'Rising beams' is a form that enables better use of the second storey. It uses beams that rise from the posts to a secondary ridge that is below the one formed by the rafters. Thatched roof farmhouses based upon the 'rising beam' structure can be further classified into four major types. The and the are rare. The latter of these, the , is popular for houses. Far more common are the (also known as ) and the types. The style has rafters, crossbeams and short vertical posts to support the ridge. Historically, these posts would have extended to the ground resulting in a row of posts extending down the centre of the house and dividing it. Although these could be accommodated in the layout of the main house, they were impractical in the earth-floored entrance area—so they were omitted and a special beam structure used instead. This style was in wide use until the Edo period when a shift was made to the style (although both types had been used since historic times). The style is a simpler triangular shape with a pair of rafters joined at the top to support the ridge pole. The ends of these rafters were sharpened to fit into mortice holes at either end of crossbeam. As this system does not rely on central posts it leaves a more unobstructed plan than the style. Design of the floor plan There were two main methods for setting out the floor plan of the . The method uses a standard size of mat, whereas the method is based upon column spacing. The method works well for without central columns as the mats and the sliding partitions ( and ) can be based on a standard size. It was mainly used in in western Japan. The method has its disadvantages if used with posts because variations