Language: Mandarin Chinese
Source: Classical literature
Bǎ gū (靶箍) literally means "handle loop".
It is best translated as "ferrule", the metal fitting around the top of the handle, just under the guard. Its function is to keep the grip from splitting and ensure a good fit against the guard.1
An alternative word used is dāobǎ shù (刀把束) or "handle binder".2
For a complete overview, see: A Chinese saber glossary.
A Chinese saber ferrule of the round style. Late 18th / early 19th century.
1. Qinding Gongbu Junqi Zeli (欽定工部軍器則例) or "Imperial regulations and precedents on weapons and military equipment by the Ministry of Public Works", 1813. Chapter 36.
2. Tongwen Guanghui Quanshu (同文廣彙全書) or "Enlarged and complete dictionary" of 1704. A Qing imperial dictionary in Chinese and Manchu, each entry double-checked and approved by the Kangxi emperor.