But the earthly branches are active and the heavenly stems are passive. In other words, heavenly stems are "calculus" based on earthly branches, among which the most important algorithms are "catching five tigers" and "catching five rats". Not only the eight characters, but also the earthly branches are more valued than the heavenly stems in other traditional arts and mathematical cultures, such as "Twenty-four Mountains" and "Six hexagrams" in Kanyu.