knee-shaft

...Therefore, some swords have sleeves made of horn or other materials between them to ensure a tight fit and to cushion the impact (Mesolithic in Denmark, Neolithic in Switzerland, Han Dynasty in China, and New Guinea peoples). The handles are broadly divided into straight, rod-like handles and short, curved knee-shafts, and the curved part of the knee-shaft is called the foot. Various ways of wearing the sword, including examples of using sleeves, are illustrated in the illustrations.

*Some of the terminology that mentions "knee-shaft" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…そこで両者のあいだに角製などの袖sleeveを介在させて密着と衝撃緩和とをはかるものもある(デンマーク中石器時代，スイス新石器時代，中国漢代，ニューギニア民族例)。柄をまっすぐな棒状の直柄（なおえ）と先が短く屈曲する膝柄（ひざえ）knee‐shaftとに大別し，膝柄の屈曲部分を斧台footとよんでおく。袖の使用例を含め着装法の各種は図解にゆずる。…

※「knee-shaft」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