ōkabe-zukuri 大壁造

1　A style or method of constructing a wall, in which the basic framework for plastering is made on the exterior face of the uprights. No penetrating or horizontal timber is used except for the wide horizontal planks *nuki 貫, set into notched spaces the exact thickness of the boards. Posts with a small diameter *mabashira 間柱, are erected between 36 cm and 45 cm apart between the uprights. Wooden laths *kizuri 木摺, with a rough grain are spaced about 1.2 cm apart and hammered into the uprights with two nails for each piece of lath. Several coats of plaster *shikkui 漆喰, are then applied. The first rough coat is mud plaster *tsuchikabe 土壁, mixed with straw. The succeeding coats are each more refined until the final coat, which is carefully smoothed. The final coat was usually white, although cream and black were sometimes used. Ōkabe-zukuri was used as a fireproofing system, similar in principle to the mud-wall structure *dozō-zukuri 土蔵造, but rather less substantial, as the external plaster coating was only about 3-5 cm thick, measured from the outer face of the posts. Timber members were usually visible on the inside of the building. Buildings thus constructed were often referred to as *nuriya 塗屋. The technique was used for the walls, turrets *yagura 櫓, and keeps *tenshu 天守 of castles, and for the row houses *nagaya 長屋 and row-house gateways nagayamon 長屋門 surrounding warrior residences. Its development coincided with advances in techniques of defensive warfare which occurred in the latter half of the 16th century. Every effort was made to ensure that castles more resistant to both fire and firearms, recently introduced from Europe. Ōkabe-zukuri was also used for folk residences *minka 民家, especially town houses *machiya 町家, and their ancillary structures, from the Momoyama period onward.
The technique is particularly associated with town houses in western Japan and the Kansai 関西 region. Here, the forms of beams, brackets, cantilevered eavebeams, the ends of rafters, and the frames and lattices *kōshi 格子 of windows are often visible, albeit encased in plaster. Sometimes decorative elements were introduced; for example, ideograms seen on the facade of the Toyoda 豊田 House (1662), a cultural property in Nara. By the end of the Edo period, the decoration had become more elaborate and sculptural, and included birds, flowers or wave motifs, sometimes enhanced with color. The plastering on town houses was usually confined to the lateral walls and to the upper floor of the front and rear facades. The timber surface of structural members on the ground floor was left unplastered. Later town houses sometimes left rafter ends and the underside of the eaves unplastered.
2　A synonym for mud-wall structures *dozō-zukuri 土蔵造.