Chinese astrology is the divination of the future from the Chinese calendar, which is based on astronomy, and ancient Chinese philosophy. In particular, it is based on the sexagenary cycle of 60 years that has been documented since at least the time of the Shang Dynasty. This basic cycle has been constructed from two cycles: the 10 heavenly stems (the five elements in their yin and yang forms) and the 12 earthly branches, or the 12-year cycle of animals referred to as the Chinese zodiac. The Chinese animal zodiac also operates on a cycle of months or 'moons' and of hours of the day.
The Yin or Yang is broken down into Five Elements (Wood, Fire, Earth, Metal, and Water) on top of the cycle of animals. These are modifiers and affect the characteristics of each of the 12 animal signs. Thus, each of the 12 animals are governed by an element plus a Yin Yang Direction.
The Chinese zodiac refers to a pure calendrical cycle; there are no equivalent constellations like those of the occidental zodiac. In imperial times there were astrologers who watched the sky for heavenly omens that would predict the future of the state, but this was a quite different practice of divination from the popular present-day methods.
Although it is usually translated as 'element' the Chinese word xing literally means something like 'changing states of being', 'permutations' or 'metamorphoses of being'. In fact Sinologists cannot agree on one single translation. The Chinese conception of 'element' is therefore quite different to the Western one. The Western elements were seen as the basic building blocks of matter. The Chinese 'elements', by contrast, were seen as ever changing and moving forces or energies - one translation of xing is simply 'the five changes'.
The balance of yin and yang and the five elements in a person's make-up has a major bearing on what is beneficial and effective for them in terms of feng shui, the Chinese form of geomancy. This is because each element is linked to a particular direction and season, and their different kinds of qì or life force.