Nine is one of the most important numbers in Chinese mythology. First and foremost, this number symbolised the sky and heaven. Other examples where the number nine is incorporated into mythology includes the Nine Cauldrons and the Nine Songs.
The Nine Cauldrons had magical qualities that allowed them to judge whether an emperor's rule was good or bad, and then to change in shape accordingly. So if the cauldrons appeared in a story as small and heavy, the emperor was ruling well. If they were large and light, the reign was bad.
The Nine Songs is a myth sometimes called the Nine Summons. It related to the music Kai (the son of one of the emperors of the Golden Age, Yu) obtained from heaven. It was also thought to refer to the music used in funerals, where the soul was being “summoned” to the afterlife.
Other significant numbers in Chinese mythology included two, which related to the connection between yin and yang, and five. There were five elements, five colours, five known planets, and five senses.