Vietnamese Folklore - Square and round rice cakes - Sự tích bánh chưng , bánh dày

King Hùng the Sixth had twenty-two sons. When the King was old, he decided to descend his throne to the person who could find out the most delicious and rarest product to offer to the heaven and the earth on New Year’s Day. 
What specialties had the princes presented to their father King? Why have rice cakes become Vietnamese traditional food since then?
Vietnamese Folklore Series includes some of the most famous and typical Vietnamese folktales. The stories are retold in English and illustrated by well-known artists, helping readers understand more about Vietnamese cultures, such as traditional rice cakes, the New Year Pole, the legend of Sword Lake... 
Vietnamese Folklore Series:
•    Vietnamese Folklore: The story of a Vietnamese Cinderella - Truyện Tấm Cám
•    Vietnamese Folklore: The story of a man in the moon - Sự tích chú Cuội cung trăng
•    Vietnamese Folklore: The New Year pole - Sự tích cây Nêu ngày Tết
•    Vietnamese Folklore: Square and round rice cakes - Sự tích bánh chưng, bánh dày
•    Vietnamese Folklore: The legend of Mountain and Water Genies - Sơn Tinh, Thủy Tinh
•    Vietnamese Folklore: The legend of Sword Lake - Sự tích Hồ Gươm
•    Vietnamese Folklore: The story of Saint Gióng - Chuyện Ông Gióng