Chinese festival observed on the ninth day of the ninth month in the Chinese calendar; it is documented since before the East Han period, before 25 CE. According to the "I Ching," nine is a yang number, which is a traditional Chinese spiritual concept. According to custom, it is held that the double yang of this day is too much yang, and potentially dangerous; to protect against danger, it was customary to climb a high mountain, drink chrysanthemum wine, and wear the cleansing zhuyu plant. Other observances may include visiting the graves of ancestors, cleaning the graves, laying out food offerings, and burning incense.
