清明
The tradition of eating qingtuan at Qingming Festival evolved from the ancient Chinese Cold Food Day (one or two days before Qingming Festival). The custom on Cold Food Day is that people do not make a fire and stop cooking. People can only eat food that doesn't need to be heated. Therefore, food such as Qingtuan can be prepared a day in advance and can satisfy hunger. Later, the Cold Food Festival evolved into the Qingming festival, and qingtuan eaten on the Cold Food Festival became an essential food for the Qingming Festical in eastern and southern China.