The twelve signs are not read in isolation. The branches are arranged in a circle of twelve, and the system reads oppositions across the circle as clashes and certain sets of three, the san he or three harmonies, as compatible groups; the Ox belongs with the Snake and the Rooster in one such triad and stands opposite the Goat. These relationships, not the animal characters, are what the traditional practice actually uses, in choosing dates, in judging compatibility for marriage, and in the year-by-year almanac readings. Popular western presentations of the Chinese zodiac usually reduce it to twelve personality profiles keyed to birth years, which is a considerable simplification: the full system assigns a stem-branch pair to the year, the month, the day and the hour of birth, giving the eight characters, bazi, on which serious practice is based.
The wu xing, the five phases, wood, fire, earth, metal, water, generate one another in a fixed productive cycle, wood feeds fire, fire's ash becomes earth, earth yields metal, metal condenses water, water nourishes wood, and check one another in an interleaved controlling cycle, wood parts earth, earth dams water, water quenches fire, fire melts metal, metal cuts wood; every one of the twelve earthly branches carries one of the five phases, though because there are twelve branches and only five phases the assignment is not one-to-one, and readings of a given year draw on both the san he triads discussed here and this separate five-phase relationship between the year's branch and the querent's own natal branch.