This is an authentic Japanese roof tile called Kawara made of ceramic from early Showa pereiod (1940s).
Kawara comes in different shapes depending on purpose, regions, etc and often have meaning such as good luck, protect house.
This is shaped in Shachihoko which is an imaginary creature known as the face of tiger and body of carp and it can make rain and stop the fire when the house is on the fire so Shachihoko can be found at the castle from old days. It is so rare and unique and wonderful piece for your garden.