Kaifu - Kaifu

...The cedar planting and felling industry in the Kitayama region near Kyoto is said to have a history of over 1000 years, but the technique of growing several straight trunks from a single cedar tree (a stump), trimming off the branches from the bottom up to remove knots, and then cutting out and polishing the ones that fit the purpose is said to have begun in the Oei era (1394-1428). These cedar logs became famous after the mid-Muromachi period, when teahouse architecture developed along with the popularity of the tea ceremony. From that time on, a distinction was made between ordinary logs (Kitayama logs, white cedar logs) and rafter logs (also called kaifu) in the production area, the former being used mainly for pillars and beams in teahouses and shoin studies, and the latter for rafters and ceiling edges at the eaves. Both were heavily used in shoin studies and teahouses built in castles and mansions in the early modern period, and later came to be used in pillars and other areas of ordinary houses. ...

*Some of the terminology explanations that mention "Kaifu" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…京都に近接する北山地方の杉植伐林業は1000年以上の歴史をもつといわれるが，台杉林業，すなわち1本の杉台木(台杉＝株木)から数本の通直な幹を育て，下から順次枝を払って節をなくし，目的に合ったものから抜き伐り，磨いて利用する〈磨丸太〉の技法は，応永年間(1394‐1428)に始まると伝えられる。この台杉丸太が著名になるのは〈茶の湯〉の流行につれて，茶室建築の発達する室町中期以後であるが，そのころから産地では普通丸太(北山丸太，白杉丸太)と垂木丸太(カイフともいう)の別を生じるようになり，前者はおもに茶室･書院の柱や桁に，後者は軒先の垂木や天井縁に用いられた。この両者とも近世の城郭や邸宅内に設けられる書院･茶室には重用され，その後は普通住宅の柱などにも多く使用されるようになった。…

※「カイフ」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