Kirosan Observatory

Kirosan Observatory on Oshima Island in Ehime was designed by architect Kuma Kengo and opened in 1994. Rather than placing a visible structure atop Mt. Kiro, Kuma cut a slit into the leveled peak and built the observatory inside the mountain itself. Visitors climb through a concrete corridor that opens into an open-topped structure with stairs and walkways branching in different directions. Each section of the route reveals a different angle across the Seto Inland Sea, Kurushima Strait, and the surrounding islands. There is no single designated viewpoint, so the experience unfolds gradually as you move through the architecture.