The Mid-Autumn Festival (中秋節; pinyin: zhong1 qiu1 jie2), Moon Festival, or, less commonly, Mooncake Festival (月餅節; pinyin: yue4 bing3 jie2) is a traditional Chinese festival on the 15th day of the 8th month of the Chinese lunar calendar (usually around mid- or late-September in Gregorian Calendar). On this day the full moon is at its roundest and brightest, which symbolises family unity and togetherness. According to Chinese traditions, on this day family members and friends will gather to visit scenic spots, gaze at the moon, and eat mooncakes and pomeloes together.
The origin of the festival is not very clear. It is said that the festival originated from ancient times, when people held ceremonies in honor of the Moon Goddess, or to celebrate the mid-autumn harvest.
However another version is that the Mid-Autumn Festival commemorates the uprisings in China against Mongols in the early 14th century. Because unlike the Chinese, Mongols did not eat mooncakes, the rebels hid a small piece of note detailing rebellion plans inside a mooncake, which was then smuggled to compatriots.Origin