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 comes with a photo booklet that lets you fully enjoy the visuals of the grown-up NiziU, as well as a trading card in daily outfits and an ID photo-style photo card, both randomly included. [Limited edition (CD + booklet) contents] a slipcase BOX and digipak specification, a flyer with an application code (valid only in Japan), a trading card limited edition ver. (randomly selected from nine kinds / nine solo designs with printed handwritten signatures), a trading card daily outfit ver. (randomly selected from nine kinds / nine solo designs with printed messages and signatures), a business card-style card, an ID photo-style photo card randomly selected from nine kinds, a 36-page newly shot photo booklet, and a sticker sheet.