The Chinese Jian is a straight sword which first appeared about 2,5000 years ago. The first Chinese sources mentioning the Jian date to the 7th century BC during the Spring and Autumn Period.
One of the earliest specimens is the bronze Sword of Goujian, and the shape of the handle and blade, and types of fittings have evolved over the years. While most are double-edged, the single-edged Tang Dynasty jian influenced the development of Japanese Katana.
Historical one-handed versions have blades varying from 18 to 31 inches. The average weight of a 28-inch blade would be 1.5 to 2 pounds. Some styles of Chinese martial arts, like Ba Gua Zhang, use two handed versions.
The Jian is considered to be a gentleman’s weapon-- as opposed to the curved single-edged Dao broadsword which was a military sword. It is also more difficult to learn than its curved counterpart.