South Korean girl group AOA perform R&B-influenced pop. Along with subgroups AOA Black, AOA White, and AOA Cream, the core quintet veer toward the sweet side of the K-pop spectrum, favoring ballads and upbeat dance tracks. Debuting in the mid-2010s with the Japanese release Ace of Angels, they hit a chart peak in 2017 with their first Korean-language full-length, Angel's Knock, which was a Top Five hit in their native South Korea and on the U.S. World chart. Formed in 2012 by FNC Entertainment, AOA -- "Ace of Angels" -- debuted as an octet with members Jimin Shin, Yuna Seo, Chanmi Kim, Hyejeong Shin, Seol-hyun Kim, Mina Kwon, Youkyung Seo, and Choa Park. Their first EP, Angel's Story, contained the single "Elvis" and peaked within the Top Ten of the Korean charts. The Wanna Be EP followed with the single "Get Out." At the end of the year, a subunit was created, dubbed AOA Black, comprised of Youkyung, Jimin, Yuna, Choa, and Mina. They released the "Moya" single in 2013, as the main group issued the two-track Red Motion EP. In early 2014, "Miniskirt" was released, becoming their most successful single to date. Short Hair arrived that summer, continuing their rise into the Top Five of the Korean charts. At year's end, their third release, Like a Cat, became AOA's first release to chart in the United States. A Japanese version was delivered in early 2015, leading to Japanese chart success and a Korean reality show. That summer, they made their American debut, performing for fans in Los Angeles and New York. "Heart Attack," from the EP of the same name, peaked at number two on the Korean charts and became AOA's second song to chart on Billboard. By 2016, a new subgroup, AOA Cream, was formed, with Chanmi, Hyejeong, and Yuna at the helm. AOA's fourth EP, Good Luck, was issued that summer, months before Youkyung departed from the group. The following year, AOA released their first Korean-language full-length, Angel's Knock. It rose to the Top Five of the Korean and Billboard World charts. Knock would be Choa's final appearance with the group, as she parted ways with AOA that summer. The group carried on and maintained course with the 2018 EP, Bingle Bangle. The following year, the group lost another member, Mina, who parted ways with AOA in April. A few months later, they issued their sixth EP, New Moon, which was their sixth consecutive Top Three showing on the Korean charts. By 2020, yet another drop in their ranks left them as a quartet when leader Jimin left both AOA and the entertainment industry. ~ Neil Z. Yeung, Rovi