Musical instruments were traditionally classified into 8 categories known as bayin.[2] Traditional music in China is played on solo instruments or in small ensembles of plucked and bowed stringed instruments, flutes, and various cymbals, gongs, and drums. The scale is pentatonic. Bamboo pipes and qin are among the oldest known musical instruments from China; instruments are traditionally divided into categories based on their material of composition: animal skins, gourd, bamboo, wood, silk, earth/clay, metal, and stone. Chinese orchestras traditionally consist of bowed strings, woodwinds, plucked strings and percussion.