T-ara
In 2011, T-ara released the song "Roly-Poly". It became the best-selling single of the year on the Gaon chart in South Korea. The group also became popular in Japan. Later that year they signed a contract with agency J-Rock to manage their sales in Japan. The contract was for USD 4.7 million. This was the most any Korean girl group had made in a foreign market at the time. T-ara went on to make a Japanese studio album called Jewelry Box. This album reached number one on the Oricon weekly charts in Japan. Also in 2011, T-ara released the Korean album Black Eyes. It lead to three number ones songs in a row. These were "Cry Cry", "We Were in Love" and "Lovey-Dovey".