The Furude Shrine is the shrine of Oyashiro-sama, the god of Hinamizawa, and the place where the Watanagashi Festival is held in every year. Originally the Furude Family lived there, but after the priest and his wife died, their daughter, Furude Rika, decided to live in a small house with Satoko near the shrine and on its grounds. Behind the shrine, there's also a small building, the Saiguden, where various torture tools are held from the dark history of Hinamizawa.
The shrine appears many times in the story, mostly as the place where Rika is killed a few days after the Watanagashi Festival.
