NiziU gave fans their first look at what's coming next with a performance teaser for 'Sour Grapes,' the title track from their upcoming mini-album. JYP Entertainment released the video on September 18, offering choreography snippets set to an upbeat soundscape the label describes as reminiscent of popping grape seeds.

The teaser emphasizes a shift in direction for the group. Sharp lighting and vibrant styling frame dynamic, large-scale movements and intense expressions, presenting what the announcement calls "a new NiziU not seen before." The song's energy and visual treatment signal a departure from the group's previous releases.

The mini-album arrives September 28 at 6 p.m. across major music platforms. This marks NiziU's domestic release strategy — the album is their first mini-album in Japan.

The timing follows a productive touring season. NiziU completed their solo arena tour 'NiziU Live with U 2026 "NEW EvoNUtion"' across five Japanese regions with 12 shows, then wrapped their second dome tour, "NiziU : THE CINEMA." Both runs demonstrated the group's growing stage presence and fanbase.

NiziU has also proven chart success in Japan's competitive music landscape. Their debut single 'HEARTRIS' won music show trophies in October 2023, and their second single 'LOVE LINE, Destiny Line' did the same in March 2025, establishing them as a consistent performer on domestic charts.

With 'Sour Grapes,' the group is positioned to expand that streak. The single's fresh production, combined with upgraded choreography and NiziU's sharpened stage skills, has drawn attention from music industry observers ahead of the release.