Collective Housing 20K is a residential complex located in Shinjuku, Tokyo, completed in 2004. Designed by Hisatsune Kitayama and Architecture Workshop, this project represents a thoughtful approach to contemporary urban housing. The building demonstrates innovative design solutions for compact living spaces while maintaining functionality and aesthetic appeal. Its architectural language reflects early 2000s Japanese residential design philosophy, balancing efficiency with livability. The project showcases how collaborative architectural practice can create meaningful housing solutions within the constraints of Tokyo's dense urban environment.