BaZi, “八 Ba” means eight and “子 Zi” means character. The eight Chinese characters are derived from the 夏历 Xia/HSIA farming calendar, also known as 万年历 the “Ten Thousand Year Calendar”, which indicates the season’s transition time and the planetary cycles at given time.
The HSIA calendar has 60-year cycles. Each cycle consists of one upper and one lower character for any given time. The upper characters are called 天干 10 Celestial/ Heavenly Stems. The lower characters are called 地支 12 Terrestrial/ Earthly Branches.
A plotted eight characters chart based on the HSIA calendar is also known as “BaZi” Ming Pan (Eight characters of life) or 四柱 Four Pillars of Destiny. Not limited but BaZi is primarily used for fate calculation and future prediction.