What musical instrument does the elegance in Li Ping's Poems of Tang Poetry refer to?

First of all, according to the description of the number of strings and the expression of timbre in the poem, Li Ping refers to the "vertical" shaped like a harp.

There are two main types of walking: one is lying, which appeared in the Spring and Autumn Period and the Warring States Period. In the Han Dynasty, as a representative musical instrument of "China Zheng Sheng", it was recorded in Shang Qing's music, mostly with five or seven strings, similar in shape to guqin, but smaller, and having the same "quality" and "phase" as pipa. In Peacock Flying Southeast, most of the hostesses are liars;

The second is the harp, with 23, 22, 16, 7 strings. It is an ancient musical instrument that flowed into the Central Plains from the Han Dynasty and gradually declined after14th century. Compared with the modern harp, the timbre is brighter.

It is worth mentioning that in ancient books, the word "graceful" does not only refer to two kinds of real graceful: upright graceful and lying graceful; In fact, all kinds of musical instruments that look like foreign harps are often collectively referred to as elegance.

Off-topic: There is a simple way to identify the names of the most traditional ancient Central Plains musical instruments and those later introduced to China, that is, the names of local musical instruments generally have only one word, such as Sheng, Xiao, Di, Qin, Qi, cymbals, drums, Qing and so on; Foreign musical instruments have longer names, such as pipa and huqin.