Chichu Art Museum was constructed in 2004 in Kagawa, Japan, with the goal of rethinking the relationship between nature and people. The museum was primarily built underground to preserve the pristine natural scenery of the Seto Inland Sea. Despite its underground location, the museum allows an abundance of natural light to enter, which changes the appearance of the artwork and the ambiance of the space throughout the day and across the four seasons of the year. As the artists and architects collaborated, the entire museum can be seen as an extensive site-specific artwork. Visitors can experience changes in both the scale and quality of light as they move through the space, and the mark represents the scale shift of natural light that brightens up the space. The flexible letter C is used to create the identity system.