Babymetal performs at Summer Sonic Festival in Chiba, Japan, on Aug. 20, 2017. Taku Fujii Babymetal rocked the crowd at the Summer Sonic music festival Sunday (Aug. 20) in Chiba, Japan, with an exhilarating concert experience that blends J-pop idol entertainment with excellently orchestrated metal. When the Japanese teen rock idols performed at Summer Sonic for the first time in 2012 they were the