The Tortoise/Dragon, Phoenix, Tiger, and Dragon originated in China and became widely adopted in Korea and Japan.
Each major direction is associated with an animal.
Tortoise/Dragon represents the East.
Tiger represents the West
Tortoise occupies the North
Scarlet or vermilion bird occupies the South
This tradition is ancient; at least since 3000 BCE and perhaps earlier.
In Japan the Four Animals became associated with Guardian Spirits
Names of the Four Animals in Japanese, Korean, & Vietnamese
Coursera Lecture on the Animals
View Directions in China in a larger map