The Book of Songs is the beginning of ancient Chinese poetry. It is the earliest collection of poems. It collects poems from the early Western Zhou Dynasty to the middle Spring and Autumn Period (11th century BC to 6th century BC). There are 311 poems in total, 6 of which are Sheng instruments. The poems, which only have titles but no content, are called six Sheng poems ("Nanbei", "Baihua", "Huashui", "Yougeng", "Chongqiu" and "Youyi"), reflecting the social outlook of about 500 years from the beginning of the Zhou Dynasty to the late Zhou Dynasty.