NiziU created a social phenomenon with "Nizi Project" in 2020, and even during the COVID-19 pandemic, they delivered smiles and happiness to the world with their energy and presence full of "euphoria." Now in their 6th year of activities and still continuing to evolve, they release their first best album "Portfolio," which condenses their own journey. This work contains 20 tracks covering NiziU's signature songs, allowing listeners to trace the path of their growth. The limited edition, based on the concept of a "gift box," comes with a Blu-ray containing talks looking back on their activities to date and interviews in which they speak deeply about their journey as artists, as well as deluxe goods such as a neck strap and a mini CD keychain, special photo card sets, and more, making it a package that naturally makes you want to pick it up. [Limited edition (CD + Blu-ray + goods) contents] a deluxe BOX special specification, a flyer with two application codes (valid only in Japan), a set of nine trading cards limited edition ver. (solo designs with printed messages and signatures), an original neck strap, a mini CD-style keychain, a mini jacket card set, an original paper file, a set of nine ID card-style photo cards, a set of nine resume-style photo cards, a sticker set, a 24-page lyrics booklet, and a 28-page newly shot photo booklet.