This 689 sq. ft. apartment redesign is called the Fujigaoka M and was done by Sinato Architects in Tokyo.
They created an L shaped wall to separate space for two bedrooms inside. This wall has built in shelves, storage, and a seating area.
According to Dezeen, the apartment is lived in by a married couple who also wanted to have a guest bedroom.
689 Sq. Ft. Modern Apartment Redesign for Married Couple

Images © Toshiyuki Yano/Sinato