Bazi means eight elements. These eight elements can be divided into Four Pillars: Year Pillar, Month Pillar, Day Pillar and Hour Pillar. Each Pillar has two parts: the Heavenly Stem and the Earthly Branch.
Chinese Astrology can be dated back to 220 AD. The theory categorizes energy into five elements: wood, fire, earth, metal and water. Each of these elements can have a yin characteristic or a yang characteristic. For example, yin earth could be the soil and yang earth could be a mountain. Using these energies, the Universe (Heaven Stem) and the Earth (Branch) will have one of these type of energies for each of the year, month, day and hour. For example, your birth day might have a Heavenly Stem of Yin Earth and an Earthly Branch of Yin Metal. A birth Heavenly Stem of Earth would indicate person who is usually very trustworthy.
By looking a persons birth chart, you can discern characteristics, skills or challenges that will pretty much follow that person throughout their life. If you compare a persons birth chart with last year's pillar, you can give provide some details about that persons life last year. If you compare the birth chart with this year and next year, this is where you can provide information to assist a person with some decisions that may come up.
By looking at your chart, you can discover many things about yourself. For example, each of us has challenges in our life. If we look back at our personal history we can see cycles of our own behavior. Some of our behaviors help us while other parts can upset our peace or cause issues with our relationships.
If you look at your horoscope it can help you with decisions like setting a direction or targeting a goal. It is a little bit like checking a weather forecast ... maybe you should take an umbrella with you or maybe a winter jacket
When looking at your birth chart, you can see some of your challenges and face them by putting them in the light. Over time, by repeatedly putting your challenges in the light, the habitual thinking loses it's power over you. With greater awareness you gain more freedom.