At the end of one year, Emperor Hung Vuong met with all his sons and announced that whomever among the princes that brought him the most special and unusual food would inherit the throne.

In response to the emperor’s wish, some princes went to the mountains. With the help of the local people, they searched for very rare fruits and special grain foods.

Some others sailed out to the open sea, trying to catch fish, lobsters and other much-loved seafoods. With these special food sources, they planned to cook tasty dishes to please the emperor.

Other princes went to the jungle to hunt. They set traps to catch birds and other wild animals. These meats were taken home to be prepared into the most palatable dishes.

In his search, prince Tiet Lieu went back to the countryside. He saw that the rice in his paddies was ripe and ready to be harvested. Walking by a fertile rice field, he picked some golden grains on a long stalk and smelled their delicate aroma.

Tiet Lieu went home with the rice stalk and told his wife that since they were farmers living off the land, they should not look anywhere else for the gifts. He said the use of the rice which they had grown with their own hands would add more meaning to the gifts, and so they used it to make special cakes for the emperor.

On the first day of Spring, the princes took the gifts of their labor and love to the emperor. All the foods were delicately and beautifully cooked.

When it was Tiet Lieu’s turn to present his gifts, he offered two kinds of cakes. The round cake was called "Banh Day," made with fine flour from ground rice grains and mixed with water into a soft glutinous paste. The square-shaped cake was called "Banh Chung," made with rice and mung beans, and wrapped in green banana leaves. Both were cooked thoroughly.

Seeing Tiet Lieu’s simple offerings, other princes sneered at them. But after tasting all the foods, emperor Hung Vuong decided that the prize should be awarded to Tiet Lieu.