The Double Ninth Festival ,bserved on the ninth day of the ninth month in the Chinese calendar, is a traditional Chinese holiday, mentioned in writing since before the East Han period (before AD 25).

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According to the iuxue86.com I Ching, nine is a yang number; the ninth day of the ninth lunar month has too much yang (a traditional Chinese spiritual concept) and is thus a potentially dangerous date. Hence, the day is also called "Double Yang Festival" .o protect against danger, it is customary to climb a high mountain, drink chrysanthemum wine, and wear the zhuyu plant, Cornus officinalis. Both chrysanthemum and zhuyu are considered to have cleansing qualities and are used on other occasions to air out houses and cure illnesses.