The turtle, dragon, tiger and rose finch each govern one direction. In traditional Chinese cosmology, space was divided into four directions, each of which had seven stars. Because the seven northern stars formed the outline of a turtle. the turtle came to represent the north.
龜能與龍、虎、朱雀各霸一方，因為在真實的大宇宙裡，古人將空間分為四方，每個方位各有七個星宿，北方七宿連結起來，輪廓像龜，因此龜成為北方的代表。