According to local folklore, deer from this area were considered sacred due to a visit from one of the four gods of Kasuga Shrine, Takenomikazuchi-no-mikoto. He was said to have been invited from Kashima, Ibaraki, and appeared on Mt. Mikasa-yama riding a white deer. From that point, the deer were considered divine and sacred by both Kasuga Shrine and Kōfuku-ji.
Killing one of these sacred deer was a capital offense punishable by death up until 1637, the last recorded date of that law having been enforced.