The festival takes place on the 15th day of the 8th lunar month. On this night, the moon is supposed to be the most round and luminous in the year. It was originally an agricultural and astrological festival held in mid-autumn, the season of predominance for the moon's female principle (yin), as opposed to that of spring, the sun's male principle (yang).
The festival has become essentially the Festival of Children. During the day, the family makes an offering of food to ancestors and deities. In the evening, adults drink tea and alcohol while gazing at the moon to foresee omens about the upcoming crop. Boys and girls sing love songs (hat trong quan) and play, performing’ the unicorn dance and procession of lanterns. They eat lunar-shaped sticky rice cakes (banh deo) and baked cakes (banh nuong). In the city, young girls show their baking skills by displaying fruits and cakes (bay co) made from custard, apples, carambolas, guavas, grapefruits, persimmons, bananas, ground sticky rice, and sugar cane. Guests come to these parties and are offered the food (pha co). Paper toys, such as: turning lamps with shades decorated with paper cut figures (den keo quan), star-shaped, toad-shaped and fish-shaped lanterns are given to the children.
