Liu Jiaxin, 12, a middle school student from Jiangbei district, Southwest China's Chongqing city, has become a grand slam winner in roller skating this year after winning the World Championship last month. The rising star grabbed the champion cups of South Korea International Open, National Championships, Asian Championship, Shanghai International Freestyle Open, and the World Championship during the past 12 months. She started to learn roller skating at the age of four and won her first championship when she was eight years. Liu was selected as a member of the national team last year.