It dates back to the Yin period in East Asia. It is said that in the Continent of Asia under the Yin dynasty Jikkan(TheTenStems) (a kind of numeral)and JUNISHI(the twelveSigns)were combined in sixty different ways to show days, months, years, and directions; JUNISHI was used to show time.
Later, different animals were used for the twelve signs of JUNISHI.。