The Double Yang Festival 重 陽 節 (Chong yang jie), also known as the Double Ninth Festival 重 九 節(Chong jiu jie) observed 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 (206 BC - AD220).

According to the Yi Ching 易經, also called "Book of Changes" - the oldest of the Chinese classic text, nine is a "yang" number; the ninth day of the ninth lunar month (or double nine) has too much "yang" (a traditional Chinese spiritual concept) and is thus a potentially dangerous date. To protect against the danger, it is customary to climb a high mountain, drink chrysanthemum wine, and wear the zhuyu (茱萸) plant "cornus officinalis" which is a kind of Dogwood. (Both chrysanthemum and zhuyu are considered to have cleansing qualities and are used on other occasions to air out houses and cure illnesses).

		Double Ninth may have started out as a day to drive away danger, but like the Chinese New Year, over time it became a day of celebration. In contemporary times it is an occasion for hiking and chrysanthemum appreciation. Stores sell rice cakes (糕 "gao", a homonym for height 高) inserted with mini colorful flags to represent zhuyu. Most people drink chrysanthemum tea, while a few strict traditionalists drink homemade chrysanthemum wine. Children in school learn poems about chrysanthemums, and many localities host a chrysanthemum exhibit. Mountain climbing races are also popular where winners get to wear a wreath made of zhuyu.
Zhuyu blossom (茱萸花)	Zhuyu fruit (茱萸果)