Shangsi Festival, also known as the Double Third Festival, is an ancient Chinese festival celebrated on the third day of the third lunar month, which falls on April 14 this year.

It is a festival mainly observed by Chinese ethnic groups, including Han and Zhuang, to ward off evil spirits and natural disasters.

The Shangsi Festival is also a day considered to be the possible birthday of the Yellow Emperor. A well-known phrase goes, "San yue san, Xuan Yuan sheng", meaning, "On the third day of the third month, the Xuan Yuan (Yellow Emperor) was born."

In 2018, the Communist Youth League's Central Committee set the third day of the third lunar month as China Huafu Day (Chinese National Costume Day), as a way to advocate the beauty of traditional Chinese clothes. The first event was celebrated on April 18 that year in Xi'an.

There are many theories about the festival's true origins. Some say it stems from a dinner party held on the banks of the Qushui River during the Zhou Dynasty (1100 - 221 BC). Others say it comes from the custom of getting rid of evil by bathing in the river. On this day, people would hold a sacrificial ceremony by the riverside to honor their ancestors, then bathe in the river with herbs to cleanse and purify their bodies. Following that, young men and women would go for a spring outing – these scenes were described in the ancient text, Shi Jing (The Book of Songs).

Shangsi Festival activities have changed with the times. The feast and praying for descendants by the river were added in the Han Dynasty (206 BC - AD 220). It was after the Wei and Jin dynasties (AD 220 - 420) that the event developed into the Double Third Day, fixed on the third day of the third lunar month.