A safe but still exciting form of football emerges

Flag football is less violent than rugby or full-contact American football. Players do not need to wear heavy protective equipment on the playground, which is one of its attractions, he said. It has been dubbed "gentle rugby" among locals.

"The flags are tied on each side of players' waists during competition. And when the defender has pulled a waist flag off the attacker, the attack is finished," Zhang said.