Kim Ji-an

Lightsum (Korean: 라잇썸; RR: Raitsseom; MR: Raitssŏm, stylized in all caps) is a South Korean girl group formed by Cube Entertainment. The group is composed of six members: Sangah, Chowon, Nayoung, Hina, Juhyeon, and Yujeong. The group debuted on June 10, 2021, with the release of their debut single album, Vanilla. Originally an eight-piece ensemble, members Huiyeon and Jian departed the group in October 2022.

The group's name, Lightsum, is a combination of the words "light" and "sum", which symbolizes "things that shine small gather together to light up the world, delivering greater positive energy through a message of hope".

2017–2020: Pre-debut activities

Juhyeon participated in The Unit: Idol Rebooting Project in 2017–2018 where she finished in 25th place. Chowon, Nayoung, and Yujeong participated in Produce 48 in 2018 where they finished in 13th place, 21st place, and 51st place, respectively. It was later revealed that Chowon was rigged out of the lineup of Iz*One, and that her real final ranking was 6th place. Juhyeon later participated in Dancing High in 2018, but did not pass the evaluation round.

Chowon was cast in Bully Bad Guys and The Dominator 3: Junior Bullies in 2020.

2021–present: Introduction, debut with Vanilla, Into the Light, and members departure

On April 15, 2021, Cube Entertainment announced that it would be debuting a new girl group, the first since (G)I-dle in 2018. The members were revealed in pairs from April 19 to 22 (in order: Juhyeon, Sangah, Chowon, Jian, Nayoung, Huiyeon, Hina, and Yujeong). A video trailer with all eight members was revealed on April 23, 2021. On May 27, it was announced that Lightsum would release their debut single album Vanilla on June 10. The group made their broadcast debut on Mnet's M Countdown on June 10 where they performed their debut single. On October 13, Lightsum released their second single album Light a Wish, with "Vivace" serving as the lead single.

On May 24, 2022, Lightsum released their first extended play Into the Light, with "Alive" serving as the lead single. On October 25, Cube Entertainment announced the departure of members Huiyeon and Jian from the group and that Lightsum would be reorganized as a group of six.

In June 2023, Sangah participated in Mnet's girl group survival show Queendom Puzzle as a contestant, she was eliminated in the first elimination rounds. On September 21, it was announced Lightsum would release their second extended play Honey or Spice on October 11.

Timeline

Extended plays

Single albums

Singles

Music videos