Language: Mandarin Chinese
Origin of term: Classical literature
Yāodāo literally means "waist saber". It is a term used in the Qing dynasty to denote a type of dāo that was worn suspended from the waist, often as part of one's official or military attire.
The name says nothing about blade shape which could theoretically be any form of dāo, even non-military niúwěidāo (牛尾刀) or straight ones like zhíbèidāo (直背刀). Most yāodāo, however, have liǔyèdāo blades as this was for long the standard Qing military side-arm, from the soldier all the way up to the emperor himself.
A typical Chinese yāodāo of the 19th century mounted in fittings for a military officer.
Blade possibly earlier. Sold by Mandarin Mansion in 2016.
Giyamz'an Namk'a, ruler of a small kingdom in present-day Sichuan Province.
He wears his straight Tibetan style zhíbèidāo as a yāodāo.
Manchu officer Baningga and his yāodāo, wearing it hilt backward in the Manchu fashion.
Deputy commander of the garrison of Chahar, he lost his life during the battle of Buraci.
Relation to pèidāo
During the Qing yāodāo (腰刀) and pèidāo (佩刀) were synonymous and in many cases used interchangeably. The term pèidāo is perhaps the more classy term of the two, seen primarily in court circles, while yāodāo was the term mostly used in state-produced regulations on arms maintenance and manufacture and of course by most Qing personnel themselves.1
Even Qianlong's own “Imperial Grand Review Pèidāo” was cataloged by his imperial household department as a yāodāo, as can still be seen from its old tag.2
1. Pu Jiang et al., eds., Huangchao Liqi Tushi (皇朝禮器圖式), or "Illustrated Regulations on the Ceremonial Paraphernalia of the Dynasty", Palace Edition of 1766 used exclusively the word pèidāo while Qinding junqi zeli (欽定軍器則例) or "Imperially Commissioned Regulations and Precedents on Military Equipment" and Gongbu Junqi Zeli (工部軍器則例) or "Regulations and precedents on military equipment for the Board of Works" of 1815 all exclusively use the word yāodāo.
2. See: Gugong Bowuyuan Cang Wenwu Zhenpin Quanji 56: Qing gong Wubei (故宫博物院藏文物珍品全集 56: 清宫武备) or "The Complete Collection of Treasures of the Palace Museum, Beijing 56: Armaments and Military Provisions", Palace Museum, Beijing. Published Hong Kong 2008. ISBN: 9789620753596.