Located on the side of Cau river, Van village in Van Ha commune, Bac Giang province, is home to Vat cau bun (mud ball wrestling), an original sport which can be found nowhere else in Vietnam.

According to village records, the festival dates back to the 6^th century when brothers Truong Hong and Truong Hat joined Trieu Quang Phuc to fight against foreign invaders. 

On the way home after their victory, they defeated black demons in a mud ball wrestling match in Da Trach marsh. Since then, Vat cau bun, also called Khanh Ha, was played to celebrate the victory of the two brothers who were honored as Tam Giang saints.