In 1991, exactly 30 years ago, River City 21 East Towers was completed as a pioneer of Tokyo waterfront development and a prototype of tower-type high-rise apartment buildings with an emphasis on views. The building is located in Tsukuda 2-chome, Chuo-ku, and although the nearest station is Tsukishima Station, it is an excellent location with smooth access from Tokyo Station and Ginza Station, and is an area with a diverse range of residents. During the Edo period, it was also called Ishikawajima, and in the modern cityscape, you can feel the Showa era history everywhere, such as Tsukishima's unique food culture and shopping streets with a downtown atmosphere, and a unique culture has been formed within the city. This project was planned with the aim of extensively renovating the group of apartment buildings (4 buildings), including the public open space, to welcome new residents and increase the asset value. [Solution] In order to solve the client's problem, we proposed a new concept of "1.5 Place," which is to create a 2nd Place function and a 3rd Place time around the 1st Place, which is the client's home. In addition, by conducting and analyzing a survey of residents, we were able to confirm that there was no discrepancy in the direction of the new rooms and spatial functions and concept design. In particular, to meet the requests of residents that were made clear through the survey analysis, we planned not only to improve the functionality of the entrance, meeting rooms, and lounges, but also to create a co-working space that assumes various ways of living, working, and gathering, and a place where communication can occur. This created a "highly social and altruistic space" and a "space whose value increases over time," which led to increased satisfaction among residents and the realization of new appeal. We also proposed a perspective on the SDGs, and not only solved the sustainable economic and social aspects that are generally discussed, but also took into consideration the living environment such as tradition, culture, and climate by understanding the location and user perspective of this project, and gave meaning to concept design concept and materials, realizing a way that was suitable for this property. In realizing these solutions, each section of our company worked together as a trinity, and by making sure to utilize design, layout planning, research, promotion, and construction capabilities, we were able to respond quickly and accurately to the customer's requests. <Our project members> [Development] Takuya Kitai, Kayu Tatsumi [Sales and project promotion] Kayu Tatsumi, Midori Nakayabu [Research and analysis] Sayuri Murata, Ai Ichikawa [General direction] no.10: Keita Aono [design, layout] no.10: Naoaki Yokoyama, Gen Tomita, Mayu Araki, Asuka Tomioka [Sign and graphic direction] no.10: Asuka Tomioka [Product management] Manabu Fukuda, Takashi Arai [Equipment design] Takaya Ota [Production, construction and site supervision] Takashi Arai, Katsumi Chikada, Kyosuke Sasa