f(x)

f(x) is a South Korean girl group formed by SM Entertainment in 2009. The group's name is derived from mathematical function notation, symbolizing transformation and adaptiveness, with "f" standing for flower and "x" for the female XX chromosome. The group officially debuted on September 5, 2009, on MBC's Music Core with "LA chA TA," a bright electropop track that introduced their dynamic concept. Their first EP Nu Abo (2010) showed early experimental tendencies with unusual time signatures. The breakthrough came with their first studio album Pinocchio (2011), whose title track "Pinocchio (Danger)" earned eight music show wins and topped the Gaon Digital Chart, with over 375,000 downloads in its first week. The repackage Hot Summer, a cover of a German song by Monrose, peaked at #2 on Gaon Digital Chart. 2012's Electric Shock EP continued their electronic sound and produced another number-one single. But it was 2013's Pink Tape that cemented their artistic legacy. The album blended electropop with R&B, hip-hop, and experimental elements, earning critical acclaim far beyond typical K-pop. Billboard later named it the greatest K-pop album of the 2010s, and Korean critics included it as the only idol album on their list of top 100 classic albums. It was also the only K-pop album on Fuse TV's "41 Best Albums of 2013" list. Red Light (2014) took a darker, more aggressive electronic direction with industrial and EDM influences, tackling themes of rebellion and societal critique. Promotions were cut short when Sulli went on hiatus in July 2014 due to health issues. She officially left the group in August 2015. f(x) returned as a quartet with 4 Walls in October 2015, a sophisticated deep house album produced by LDN Noise under Min Hee-jin's creative direction. It was widely praised as their most mature work and influenced a shift toward house music in K-pop. After the 2016 SM Station single "All Mine," the group effectively went on hiatus. Members pursued solo paths: Victoria focused on acting in China, Amber released solo music starting with her 2015 EP "Beautiful," Luna debuted as a soloist with "Free Somebody" in 2016, and Krystal pursued acting and modeling. In August 2019, f(x) reunited as a trio (without Victoria) for SM Town Live in Tokyo. As of 2025, the group has been removed from SM's official artist list, though no formal disbandment has been announced. f(x) is considered part of the "second generation" of K-pop groups (2005-2010), alongside groups like 2NE1, Girls' Generation, and SHINee.[edit]

SM Entertainment began assembling f(x) in 2008, aiming to create a girl group with a fresh, unconventional concept. Victoria was recruited after winning a dance competition in Beijing and trained for two years. Amber, discovered through SM's Global Audition in Los Angeles, brought a tomboyish image unusual for K-pop girl groups. Luna had been a trainee since middle school, known for her powerful vocals. Krystal and Sulli both joined SM as child actors and trainees. The five members trained together for varying periods before their debut was announced in August 2009. Their debut concept was marketed as "a girl group with a concept that has never been done before with a dynamic feel."[edit]

f(x)'s sound evolved dramatically over their career. Early on, they specialized in bright, upbeat electropop with quirky production. Nu Abo featured unusual song structures and vocal arrangements. Pinocchio and Electric Shock refined this sound with heavier synthesizers. Pink Tape marked a high point, mixing electropop with R&B, hip-hop, and even jazz elements. Red Light explored darker electronic territory with industrial beats and EDM influences. Their final album 4 Walls shifted to deep house and tropical house, a sound that influenced many later K-pop groups. Lyrical themes ranged from teenage romance to social commentary, with Red Light critiquing societal pressure. The group's experimental sound set them apart from other SM groups like Girls' Generation and SHINee.[edit]

f(x) was among the first K-pop groups to gain international recognition, performing at SXSW in 2013 as the first K-pop act to do so. Their experimental sound and bold concepts influenced a generation of later groups, particularly in their use of electronic music. Pink Tape is frequently cited as one of the most influential K-pop albums, inspiring a wave of artistic ambition in the industry. The group's fashion, especially Krystal and Victoria's looks, also made waves in the fashion world. Sulli's tragic death in 2019 sparked global conversations about cyberbullying and mental health in K-pop, leading to increased scrutiny of online harassment and industry practices. Sulli's suicide followed the 2017 suicide of SHINee's Jonghyun, also an SM Entertainment artist, both of whom had struggled with cyberbullying. Her diary indicated she had repeatedly asked SM Entertainment to take action against malicious comments.[edit]

f(x)'s fandom is called MeU, pronounced "Me and You." Their official fan color is Pearl Light Periwinkle. The group had an official lightstick, though its design is not widely documented. MeU has remained notably loyal even during the group's long hiatus, organizing streaming projects and social media campaigns to keep f(x)'s legacy alive. Fans often highlight the group's experimental discography and lament the lack of recognition from SM Entertainment in later years. Fan traditions include streaming initiatives and social media campaigns to preserve the group's legacy.[edit]

Krystal is the younger sister of Jessica Jung, a former member of Girls' Generation. f(x) was the first K-pop group to collaborate with actress Anna Kendrick for a comedy skit on Funny Or Die in 2013. "Hot Summer" is a Korean remake of a song by German group Monrose, produced by Thomas Troelsen and Remee. The creative director for 4 Walls, Min Hee-jin, later founded ADOR and created NewJeans. Despite their influence, f(x)'s albums remain out of print and are rarely discussed in contemporary K-pop media. The group's name is pronounced by saying the two letters individually, but is sometimes pronounced as "Effects." f(x) did not have any official sub-units formed within the group. Their first and only concert tour was "Dimension 4 – Docking Station" (2016) held in Seoul, South Korea.[edit]