Nine is the highest odd number making the ninth day of the ninth lunar month a day where the two Yang numbers meet. According to ancient customs the meeting of the Yang numbers creates too much Yang and increases the chances of danger.
In order to protect oneself from Double Ninth danger it is customary to drink chrysanthemum wine and tea. Holiday observers also consume chrysanthemum cakes and don the zhuyu plant. Both chrysanthemum and zhuyu are considered to have cleansing qualities, including the abilities to ward of illnesses and evil spirits.
Observers also celebrate the holiday by mountain climbing and visiting the graves of ancestors.
For more information about the Double Ninth Festival visit China Daily.
