A four-year experiment in making culture will take over the former Imperial Hotel Plaza Tokyo site in Marunouchi. NOT A CITY, the urban-development arm of the NOTA group founded in 2025, will open a cultural complex called NOT A MUSEUM on the grounds of the Imperial Hotel Tokyo's Tower-kan, using floors one through four of the building slated for redevelopment. Planned and operated together with the collective SKWAT, the venue is scheduled to open in summer 2027 and run until March 2031. The site centers on the former Imperial Hotel Plaza Tokyo, a luxury shopping arcade that opened in 1983 and closed in March 2024. Roughly 2,000 tsubo of space will host art, books, music, fashion, and film under the concept "CULTURE, IN THE MAKING" — a place where finished works are shown alongside the processes that produce them, rather than only polished results. SKWAT, active since 2019 under Keisuke Nakamura of DAIKEI MILLS, is known for temporarily occupying idle urban voids and reopening them to the public; DAIKEI MILLS and NOT A HOTEL ARCHITECTS will handle the spatial design. Nakamura describes the building's accumulated forty years as the asset to work with, reading its time rather than rebuilding it blank. NOT A CITY aims to give unused or finished buildings new purposes and open up their potential. Its chief executive Midori Omori said the goal is to root culture in the city and let it grow there. The group is also developing JAPA VALLEY TOKYO at Yurakucho station with Mitsubishi Estate, an art, commerce, and hospitality complex created with Pharrell Williams and NIGO that opens in spring 2027. On the 130-year-old hotel's grounds, the temporary museum turns a four-year gap before redevelopment into cultural time.