South Korean girl group, f(x), was launched by the agency SM Entertainment and consists of the members Victoria Song (Sòng Qiàn), Luna (Park Sun-yung), Krystal (Chrystal Soo Jung), Amber (Amber Liu), and Sulli (Choi Jin-ri). The group made their debut in the summer of 2009 with the single "La Cha Ta" and expanded their audience with the EP Nu ABO, which reached number 2 on the Korean charts in 2010. The following year, they achieved even greater success with both hit album Pinocchio and lead single "Pinocchio (Danger)" taking the Number 1 spot on the charts. After their first tour across Asia, their track "Hot Summer" and its corresponding eponymous album amplified their popularity, climbing to number 2, with follow up single song "Electric Shock" reaching number 3 on the Billboard World Chart. Continuing to gain momentum, Number 1 song "Rum Pum Pum Pum" climbed to the 5th position in the US, paving the way for their album Pink Tape (2013), which simultaneously topped both charts. At the peak of their success, f(x) won numerous awards, returning a year later with the house-inspired album Red LightN (2014), which reached umber 1 in South Korea and number 2 on the Billboard World Chart. At this time, Sulli decided to distance herself from the group after an intense period of activity and the group returned in 2015 to fulfill their contracts as a quartet, including a performance at a K-pop festival in London, releasing 4 Walls in the autumn, once again demonstrating f(x)'s supremacy on the charts. Following solo debuts from Amber and Luna, the group embarked on a Japanese tour in 2016, followed by several years of hiatus before a brief return to the stage in 2019 and successive announcements of departures as their contracts expired. In July 2023, the single “4 Walls” from their successful 2015 album of the same name re-emerged on the Malaysian Top 100 charts, peaking at number 91.
