What makes Otona na no yo! / 1 Oku 3 Zenman Sō Diet Ōkoku by Berryz Kobo notable?

This album features the single '1億3千万総ダイエット王国', which became a commercial success, charting well and resonating with fans for its upbeat and motivational themes. The release also showcases Berryz Kobo's continued influence on the idol genre, exemplifying their ability to adapt and evolve within the ever-changing landscape of J-pop. Released on February 19, 2014, 'Otona na no yo! / 1 Oku 3 Zenman Sō Diet Ōkoku' marks Berryz Kobo's return after a two-year hiatus. This album comes at a pivotal point for the group as they were solidifying their legacy in the J-pop scene after years of popularity, following their previous album 'Ai no Album 8' in 2012.