On June 5 (Thu) and 6 (Fri), 2025, Japanese music production company WACK held its sixth overseas concert, WACK in the UK vol.6, at the live venue The Underworld in London, UK.

WACK has previously hosted five editions of WACK in the UK at The Underworld—on November 16, 2023; March 27, August 28, and November 26, 2024; and March 26, 2025. Vol.1 featured ExWHYZ, ASP, and a special unit called AiNATOAOI—comprising AiNA THE END and dancer/model Aoi Yamada. Vol.2 showcased GANG PARADE, ASP, and KiSS KiSS. Vol.3 brought ASP, BiS, and MAMESHiBA NO TAiGUN TONAIBOUSHO a.k.a. MONSTERIDOL to the stage. Vol.4 featured ASP, ExWHYZ, and MAMESHiBA NO TAiGUN TONAIBOUSHO, and Vol.5 highlighted ASP, GANG PARADE, and KiSS KiSS in energetic performances.

This sixth installment marked the first time WACK in the UK was held across two days. Here’s a report from Day 1 of the event.

WACK in the UK vol.6 — Day 1 On-Site Report

Now in its sixth edition, WACK in the UK is a concert series that WACK organizes independently in London. With support from Tom Smith of JPU Records, WACK handles everything from venue booking to on-site logistics, making it a truly DIY production. Since its inception, over 300 fans have attended each show—many more from the UK and beyond than from Japan.

Former WACK CEO Junnosuke Watanabe, who stepped down to pursue graduate studies in the UK, now lives in the country and attends university. On January 6, 2025, he launched the English-language media platform DiG YOUR OWN IDOLS, which highlights not only WACK’s idols but also the broader Japanese idol scene and culture for English-speaking audiences.

Day 1 of this milestone 2-day event featured three groups: ASP—who have performed at every single WACK in the UK edition—as well as ExWHYZ and MAMESHiBA NO TAiGUN, both making their third appearances.

MAMESHiBA NO TAiGUN

As the unique SE featuring the voice of Kuro-chan played, the crowd began chanting “Oi! Oi!” as the five members—AiKA THE SPY, NAO OF NAO, LEONAEMPiRE, MOMOTi NGALE, and HANAEMONSTER—entered the stage. After greeting the audience in Japanese with “Nice to meet you, we are MAMESHiBA NO TAiGUN!”, they launched into their set with the song “Restart.” The crowd erupted during the intense “Gachi-koi” chants just before the final chorus, and the group kept the energy high with the punk-charged “FLASH” and “TONAi GiRL’S,” originally by TONAi BOUSHO.

Each member then introduced themselves in English. HANAEMONSTER, who had previously left the group and returned, explained her comeback to the fans and led a call-and-response using the word “demodori” in Japanese. When she shouted, “Are you ready to dancing?”, they burst into “Reload,” choreographed by AiNA THE END. This led into the ethnic dance tune “Mysterious Party” and the emotionally significant “MUST GO.”

The group followed up with “Walk,” whose music video was shot on the streets of London—making it a fitting and emotional highlight of the evening. With the audience now completely in sync, the group transitioned to the electro-dance number “Starry Carnival.” When AiKA THE SPY blew her whistle right before the chorus, the entire crowd jumped together in unison. They closed with the high-energy anthem “MAMESHiBA NO TAiGUN – This Is Our Life Theater -,” exiting the stage to roaring applause.

ASP

Next up was ASP. The group, consisting of YUMEKA NOWKANA?, NAMELESS, MOG RYAN, MATiLDER TWiNS, WONKER TWiNS, CCCCCC, RiONTOWN, and iKO MUGENNOKANATA, appeared on stage with seven members (as NAMELESS is currently on hiatus).

ASP is the only group to have performed at every single edition of WACK in the UK. The seven members entered to their familiar opening SE and launched into their set with “Tokyo sky Blues,” a high-energy electro dance-rock track that instantly ignited the floor. They followed with “Black Nails,” a digital rock track produced by the alternative unit AFJB (a collaboration between Age Factory and rapper JUBEE), and the high-octane “TOTSUGEKI!!!!!”—a quintessential ASP blend of punk and digital mayhem.

During the MC, each member introduced themselves in English and greeted the crowd with “We’re so happy to be here today!” When they announced, “Next song is ‘Japanese Girl,’” the group broke into their hard-hitting digital hardcore anthem of the same name. The mood then shifted with the cute and bouncy “Blueberry Gum,” which had the audience chanting “chu-chu!” in sync. Then came the mid-tempo, melodic “PLEASE!!!,” showcasing the group’s softer side.

With a perfect balance of intensity and emotion, they performed “darma” and “MAKE A MOVE,” captivating the crowd with their presence and stage control—proof of their growth over six UK appearances.

During the next MC, the group announced the addition of new member iKO MUGENNOKANATA, receiving thunderous applause and cheers from the audience. They immediately followed with “Get New MIRAI,” a powerful and emotional anthem produced by Age Factory. Without pause, they delivered “TOXiC iNVASiON,” originally composed by The Prodigy’s frontman Maxim, and their major debut track “Hyper Cracker,” maintaining a fever-pitch energy that brought their set to a climactic close.

ExWHYZ

The final act of Day 1 was ExWHYZ, making their third appearance in London. At their previous UK show, they performed as a trio before mayu’s official return—but this time, fans were treated to a full four-member lineup with yu-ki, maho, mikina, and mayu taking the stage together once again.

As the danceable opening SE played, the audience erupted into loud cheers and rhythmic clapping. The four members appeared and launched into their set with “SHOWTIME,” a track that fuses 90s U.S. hip-hop and rock influences. With sharp choreography and confident presence, they quickly drew the audience into their world. They followed with the high-speed “NOT SORRY,” prompting fans to call out the members’ names in unison and clap along, creating an intense connection between stage and floor. The group then transitioned into the bass-heavy “ANSWER,” performed with poise and intensity.

They greeted the crowd in Japanese with, “Nice to meet you! We’re ExWHYZ!” and each member introduced themselves in English. mayu confidently declared, “I’m back!”—marking her official return to the London stage. Next came “FURACHINA SUMMER,” a summer tune produced by Kenmochi Hidefumi of Wednesday Campanella. The set continued with “Sweet & Sour,” notable for its pounding four-on-the-floor beat and mellow chorus, and the euphoric “Fleeting,” which turned the venue into a joyous dance floor.

Before their next song, they announced that no photos or videos were allowed, as they wanted the audience to “feel it with your heart.” They then performed their latest track “iD,” a powerful dance tune with a big beat that evoked the UK club scene of the 1990s. As soon as the intro of their killer dance anthem “Obsession” began, the crowd erupted. When mikina whispered “Don’t miss this” before the final chorus, the audience’s excitement reached new heights. They closed the set with “STAY WITH Me,” during which the members and fans sang together, wrapping the show in a wave of happiness and emotion.

As the three performances came to an end, Junnosuke Watanabe returned to the stage. The three groups also reappeared, and each member shared their thoughts and appreciation in English, creating a heartwarming and joyful atmosphere.

Then came a surprise announcement—Watanabe revealed that ASP would embark on a UK tour in September. The audience roared with excitement. Details will be announced on social media in the coming weeks.

Finally, HANAEMONSTER shouted, “We are—” and the members joined hands and responded in unison, “WACK!” Thus, Day 1 came to a close amidst huge cheers and a sense of celebration.