mouth harp; Jew's harp
A small musical instrument held in the mouth and plucked; known as 口琴 in Japanese. The term 'Jew's harp' is common in English but may be considered dated or culturally insensitive by some.
He is good at playing the mouth harp.
民族音楽で口琴がよく使われる。
The mouth harp is often used in folk music.