Behind the building is the Banryutei Rock Garden, the largest rock garden in Japan. Built in 1984, its large rocks from Shikoku, the birthplace of Kobo Daishi, represent a pair of dragons emerging from a sea of clouds. The sand on the ground represents the sea. The rocks sometimes represent places related to Buddhism, sometimes literature, and sometimes animals such as this. The idea of the garden is «Two great dragons meeting at the centre of the universe».