Chinese vocal music has traditionally been sung in a thin, non resonant voice or in falsetto and is usually solo rather than choral. All traditional Chinese music is melodic rather than harmonic. Chinese vocal music probably developed from sung poems and verses with music. Instrumental pieces played on an erhu or dizi are popular, and are often available outside of China, but the pipa and zheng music, which are more traditional, are more popular in China itself. The qin is perhaps the most revered instrument in China, even though very few people know what it is or seen and heard one being played. The zheng, a form of zither, is most popular in Henan, Chaozhou, Hakka areas, and Shandong. The pipa, a kind of lute, believed to have been introduced from the Arabian Peninsula area during the 6th century and adapted to suit Chinese tastes, is most popular in Shanghai and surrounding areas.