jōyabashira 上屋柱

1　The posts which support the ends of the principal transverse beams *jōyabari 上屋梁, in the main structural frame of traditional vernacular houses *minka 民家, with thatched roofs. In cases where the roof was carried down beyond the ends of the jōyabari to create a lower peripheral zone *geya 下屋, they were also called irikawabashira 入側柱. When the geya space was incorporated into the interior of the building, jōyabashira were often left as freestanding posts *dokuritsubashira 独立柱. These were found to be inconvenient and carpenters devised various ways to eliminate them, most notably by inserting deep section lintels, sashimono 差物 or sashigamoi 差鴨居 (see *kamoi 鴨居), which spanned from posts at the center of the building to the peripheral posts or *geyabashira 下屋柱. They also supported the upper stub of the jōyabashira which was reduced to a strut *tsuka 束. Jōyabashira usually define the boundary between the jōya and geya, but in certain cases, the situation is ambiguous because the ends of the jōyabari project beyond the line of the jōyabashira.

2　In fishermen's houses gyoka 漁家, in Niigata Prefecture, a large post that was placed at the boundary of the earth-floored area *doma 土間, and the living rooms, kyoshitsubu 居室部, approximately at the center of the building's cross section. See *daikokubashira 大黒柱.