[Edaily Starin KIM HYUNSIK Reporter] Girl group LIGHTSUM (Sang-ah, Cho-won, Na-young, Hina, Ju-hyun, Yu-jeong) is returning to the spotlight with a new album after a long hiatus. Their stage, however, will be in Japan, not Korea. As they mark their sixth year since debut, the group is embarking on a new challenge: conquering the Japanese music market.

◇Songs, Choreography, Visuals… “All-In” on Localization
LIGHTSUM will release their debut album “Re:idol” in Japan on the 23rd. This marks the first time LIGHTSUM—launched by Cube Entertainment in June 2021—has released an album in Japan.
“Re:idol” also marks the group’s first new release as a full six-member lineup in approximately two years, following the release of their digital single “POSE!” in August 2024. On the 16th, LightSome pre-released the album’s title track, “Doushite” (どうして), to kick off promotions for their Japanese debut.
It is not unusual for K-pop idols to release full-length albums and promote in Japan. However, LightSome has drawn attention for actively researching Japanese idol culture and fan preferences from the album production stage onward, undertaking a bold transformation reminiscent of local girl groups.
Lightsome has gone a step further than simply translating existing songs into Japanese or replicating the K-pop style as-is. The lyrics and composition for the new songs included on the album were created in Japan, and the choreography was also completed in collaboration with local production teams.
Ran, the choreographer behind the hit song “Idol” by the popular Japanese music unit Yoasobi, participated in creating the choreography for the title track “Dosite.” Ran incorporated movements that intuitively express the meaning of the lyrics into the choreography, such as using the Japanese word “kyun” (キュン), which refers to the feeling of a fluttering heart.
The album’s concept prominently features the “kawaii” (カワイイ, cute) aesthetic, which is familiar in the Japanese idol market. In the images released ahead of the album’s release, the members drew attention by showcasing a glamorous and cute atmosphere unique to Japanese idols—a stark contrast to their previous activities—through princess-style accessories such as ribbons, lace, and tiaras.
A representative from Cube Entertainment explained to Edaily on the 21st, “Our Japanese debut album holds great significance as a challenge to expand our activities into a new environment,” adding, “Based on the musical capabilities and individual personalities the members have cultivated since their debut, we explored ways to connect more closely with local Japanese fans.” The representative further elaborated, “Through that process, we prepared a project that understands the culture of Japanese idols and local fans and interprets it through LightSome’s unique style.”

◇ Experiencing Japanese Idol Culture… The Journey of a Fresh Start Captured in a Documentary
Lightsum generated buzz by turning their preparations for their Japanese debut into content. Through the local OTT platform ABEMA, they unveiled a seven-part documentary series titled “Re:Idol”—the same name as their album—revealing the process of finding a new identity and the members’ inner struggles.
Member Yoo-jeong also opened up about her changed mindset as she adapted to the new project. She said, “I think I’ve been overthinking things too much lately. Having this new experience actually feels like I’m returning to my true self, which is enjoyable.”
Lightsome also had the opportunity to experience Japanese idol culture firsthand. In Episode 3 of the documentary, they visited “Super NATSUZOME 2026,” a major outdoor idol festival in Japan, to watch performances by local idols.
After watching the performance by the Japanese group ROOKEY♡ROOKEYS, the members said, “Seeing the Japanese idols perform with such passion without taking a break made us wonder if we could perform with as much energy as they do.” They added, “We had just been vaguely hoping things would work out, but this made us think seriously about what we need to do to make our group known to more people.”
The final episode, released on the 20th, also featured the members’ candid reflections on their nearly two-year hiatus from group activities.
Sang-ah said, “It was hard for all of us during those two years off, but we tried our best not to let it show. We didn’t want to show the agency that we were exhausted.” She continued, “Having an empty schedule was the most upsetting part, but recently, our schedules have become so packed. Rather than feeling tired or worn out, I’m just so happy.” The Lightsome members also expressed their hope on the show, saying, “We hope to become a group that can keep performing for a long, long time without taking a break.”
Since the release of their album, Lightsome has been meeting local fans in Hokkaido, Tokyo, Osaka, and other locations through mini-live performances, high-touch events, autograph sessions, and two-shot photo sessions. On the 26th, they will also take the stage at “SBI Music Circus Hokkaido 2026,” held at the Daiwa House Premist Dome in Hokkaido, Japan.
A representative from Cube Entertainment emphasized, “Our primary goal is to solidify the group’s foundation by consistently engaging with fans to firmly establish the group’s presence.” The representative added, “We plan to expand Lightsum’s scope of activities by creating opportunities not only in Japan but also in Korea.”