In ancient China, each day in the new year's week was designated as the day of a certain animal, with the first day as the day of the rooster, the second day as the day of the dog, the third the boar, the fourth the sheep, the fifth the ox, the sixth the horse respectively.
古来中国では、正月の1日をニワトリの日、2日を狗（犬）の日、3日をイノシシ（ブタ）の日、4日をヒツジの日、5日をウシの日、6日をウマの日としていた。