Population growth of Japan has continuously decreased since 2010, due to the high life expectancy and low birth rate. "Old School x New Hybrid: Designing the Rural Areas of Japan" addresses the pressing issue of Japan's aging population and depopulation. With a focus on Haboro Town in Hokkaido, a region grappling with demographic shifts, I explore the transformation of an abandoned school, Taiyo Elementary, into a hybrid space combining congregate housing and a children's hall (Jidoukan). The design aims to foster community engagement and social cohesion by integrating seniors and children. Through coexistence, preservation, and managing decline, my thesis offers a relational solutions for supporting local communities, countering isolation, and adapting to demographic change.