The ruan (阮, pinyin: ruǎn) is a Chinese plucke string instrument. It is a lute with a fretted neck, a circular body, and four strings. Its strings were formerly made of silk but since the 20th century they have been made of steel (flatwound for the lower strings). The modern ruan has 24 frets with 12 semitones on each string, which has greatly expanded its range from a previous 13 frets. The frets are commonly made of ivory. Or in recent times, metal mounted on wood. The metal frets produce a brighter tone as compared to the ivory frets.