The Mud ball wrestling festival is held from April 12-13-14 every two Lunar years in Van Village, Bac Giang - one Northern province of Vietnam. This unique festival is to memorize the victory of four brothers Truong Hong, Truong Hach, Truong Lung and Truong Lay who defeated a group of demons in a mud ball wrestling match in a marsh in the 4th- 5th century. In this game, selected strong men in their village will try to score a 'goal' by carrying a 20kg wooden ball - 40cm in diameter , to one end of the muddy hole, each team has 8 members. This festival is a feature of wet rice culture, showing the desire of farmers for a year of good weather and bumper harvests.