Every BaZi chart is built from the same 22 building blocks: 10 Heavenly Stems and 12 Earthly Branches. Once you understand these, the entire system becomes logical rather than mysterious.
The 10 Heavenly Stems (天干)
The Heavenly Stems represent the Five Elements in both Yang and Yin form. Each stem has a name, an element, and a character in Chinese:
| Stem | Chinese | Element | Polarity | |------|---------|---------|---------| | Jia | 甲 | Wood | Yang | | Yi | 乙 | Wood | Yin | | Bing | 丙 | Fire | Yang | | Ding | 丁 | Fire | Yin | | Wu | 戊 | Earth | Yang | | Ji | 己 | Earth | Yin | | Geng | 庚 | Metal | Yang | | Xin | 辛 | Metal | Yin | | Ren | 壬 | Water | Yang | | Gui | 癸 | Water | Yin |
The Heavenly Stem of your Day Pillar is your Day Master — the most important character in your chart.
The 12 Earthly Branches (地支)
The 12 Earthly Branches are the familiar animals of the Chinese zodiac, but they contain more information than their animal names suggest:
| Branch | Animal | Element | Hidden Stems | |--------|--------|---------|-------------| | Zi | Rat | Water | Gui | | Chou | Ox | Earth | Ji, Gui, Xin | | Yin | Tiger | Wood | Jia, Bing, Wu | | Mao | Rabbit | Wood | Yi | | Chen | Dragon | Earth | Wu, Yi, Gui | | Si | Snake | Fire | Bing, Geng, Wu | | Wu | Horse | Fire | Ding, Ji | | Wei | Goat | Earth | Ji, Ding, Yi | | Shen | Monkey | Metal | Geng, Ren, Wu | | You | Rooster | Metal | Xin | | Xu | Dog | Earth | Wu, Xin, Ding | | Hai | Pig | Water | Ren, Jia |
The hidden stems within each branch are crucial — they add elemental complexity that isn't visible from the branch's primary element alone.
How They Work Together
A BaZi chart contains four Stems (one per pillar, on top) and four Branches (one per pillar, on bottom). The stems interact with each other on the surface; the branches interact with each other below; and stems interact with the branches of the same pillar vertically.
Stem combinations (合): Certain stem pairs combine to create a new element. For example, Jia (Wood) and Ji (Earth) combine to create Earth. These combinations create new elemental energy that modifies the chart.
Branch harmonies: Six Harmony (六合) pairs and Three Harmony (三合) trios create favorable combinations that smooth the chart's energy.
Branch clashes (冲): Opposing pairs (Rat-Horse, Ox-Goat, Tiger-Monkey, Rabbit-Rooster, Dragon-Dog, Snake-Pig) create dynamic tension and disruption when activated.
The 60-Year Cycle
Because there are 10 stems and 12 branches, they combine in a cycle of 60 unique pairings (the LCM of 10 and 12) — which is why the Chinese calendar operates on a 60-year cycle. Within your lifetime, you experience each year of the cycle once, and your chart's interaction with each year is unique.