Large sparse rafters - Oobabarataruki

…In the Japanese style, the rafters at the corners on the outside of the beams are not placed on the beams, but are placed between the corner beam and the wooden beam or thatch beam, and are called distributed rafters. Among parallel rafters, those that are closely spaced are called shige rafters, those that are sparse are called sparse rafters, and those with two or three between pillars are called oosabara rafters. In ancient times, rafters were thick and widely spaced, and the spacing varied depending on the pillar, but from the Middle Ages they gradually became thinner, and in the late Kamakura period, the rokushigake method, in which six rafters are placed neatly on top of a mitou (a square), emerged, and the dimensions between pillars came to be determined in units of rafter spacing. …

*Some of the terminology explanations that refer to "large sparse rafters" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…和様では，桁から外側の隅の部分の垂木は，桁にはのらず，隅木（すみぎ）と木負，茅負の間にかけられ，この垂木を配付（はいつけ）垂木と呼ぶ。平行垂木のうち，間隔の密なものを繁（しげ）垂木，疎なものを疎（まばら）垂木といい，柱間に2～3本のものは大疎（おおまばら）垂木という。古い時代には，垂木は太く，間隔も大きく，また柱間によって間隔に違いがあったが，中世からはしだいに細くなり，鎌倉時代の後期に，三斗の上にきちんと6本の垂木がのる六枝掛（ろくしがけ）の方式が発生し，柱間寸法を垂木間隔を単位として定めるようになる。…

※「大疎垂木」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報