Some researchers think that the celebration has its origin in China. There is a legend Qu Yuan – Chinese poet who lived during the Warring States period of ancient China. In Vietnam, we call him Khuat Nguyen.
He was a faithful person but living in the empire in decline. He hindered the king from making some bad decisions. Other officials devised false stories about him. The king did not follow his advice and hated him. He was so sad and drowned himself in the Mich La, China on May 5th of the lunar calendar.
Chinese people regretted the person having a clear heart. Every year, on this day, people made cakes with five-color strings and dropped them to the river to offer Khuat Nguyen. They tied five-color strings on the cakes in order to make fishes afraid and do not dare to eat the cakes. They also poured rice into bamboo tubes and dropped them into the river. The custom gradually spread through some nearby countries.
Vietnamese people call this day Worm-killing Festival because most farmers start killing worms on their rice fields and orchards. Vietnamese ancestors had told us a story about Doi Truan who taught farmers how to kill a lot of worms in fruits and rice. He offered Banh gio (a kind of Pyramid sticky rice cake), fruits to Gods in front of a house.
He told that if all farmers did the same things on the same day every year, all worms will be weaker and killed easily. The man had disappeared after helping killing worms. Nowadays, grandparents tell their children about the stories, teach them to be grateful to their ancestors and the country’s tradition.