The purpose of Chinese astrology is direct - to define 'cures' for unfortunate stars by correcting imbalances in the natal chart. Thus, systems like Feng-Shui use the astrological chart as a starting point to prescribe ways to bring balance into one's life. The concept of balance and of Yin and Yang is one that is vital to every aspect of Chinese astrology. Each animal, each element and each year is either Yin (soft) or Yang (hard). Every person born in a particular year doesn't share the exact same fate and personality. To refine predictions, Chinese astrology uses a complex system of twelve Palaces, similar to the twelve astrological Houses in Western astrology. Zi Wei Dou Shu is used to create a person's entire astrological chart by assigning each of the 'stars' to a Palace. It is the arrangement of these Palaces and stars that determine the influences that a person must affect in order to affect his fate.
Chinese astrology is based on cycles of 60 years. Each year is assigned both one of the 12 animals and one of the five elements - wood, water, air, earth and metal - and so the years are more properly defined as the Year of the Water Tiger, The Year of the Earth Pig and so on - sixty in all