BaZi is an ancient art of deciphering destiny and luck. It was founded in Han dynasty, developed during Tang and Song dynasties. It was widely used during Ming and Ching dynasties. BaZi today is the result of refinements over the years.
The word BaZi (八字) means eight characters in Chinese. It is actually the date and time of birth expressed in eight special Chinese characters. These eight characters are often displayed as four pillars (i.e. four columns) of characters; as a result, BaZi is also known as Four Pillar (四柱). The four pillars of characters express the qi (i.e. cosmic energies) of the year, month, day and hour at the moment of birth.
A BaZi has two components: Destiny Chart (命盘) and Big Luck Cycle (大运). Destiny Chart is the destiny component. It is also known as the BaZi. The Destiny Chart holds the code to a person's destiny. Analyzing the Destiny Chart would decode what destiny indicates about affinity for friends, siblings, father, mother, talent, wealth, career, marriage, etc.
The Big Luck Cycle is the luck component. It is a series of two Chinese characters arranged in pillar form. Each pillar represents the qi in a 10-year period. The Big Luck Cycle holds the code to a person's luck. Analyzing the Big Luck Cycle and its interactions with the Destiny Chart would decode how luck changes through time.
According to BaZi studies, both destiny and luck play important role in a person's fortune. An analogy of a person's life journey is a car on a long journey. A car journey (i.e. life journey) is good or bad depends on the car condition (i.e. destiny) and the road condition (i.e. luck). The car journey would be smooth if the car condition is good and the road is not bumpy. The car journey would not be so smooth if the car condition is not so good and the road is bumpy.