Basics · what the eight characters are
A ba zi chart is eight characters: four pillars, and each pillar is one stem on top of one branch. Two of the eight are the self and its seat; the other six describe the surroundings. Almost every beginner error is a boundary error, so this page settles the two boundaries before anything else.
Enter a birth date and each of the eight characters is labelled as a stem or a branch, with its element and polarity.
The worked example is 1985-07-04 12:00, male. Every example chart on this site uses the same one so the pages can be read against each other.
| Pillar | Stem (above) | Branch (below) | Stem element | Branch element |
|---|---|---|---|---|
| Year pillar | 乙 Yi | 丑 Chou Ox | Yin Wood | Yin Earth |
| Month pillar | 壬 Ren | 午 Wu Horse | Yang Water | Yang Fire |
| Day pillar | 甲 Jia | 辰 Chen Dragon | Yang Wood | Yang Earth |
| Hour pillar | 庚 Geng | 午 Wu Horse | Yang Metal | Yang Fire |
Ten stems against twelve branches looks like 120 pairs, but only 60 of them exist: the stem and the branch must share the same polarity. The grid below marks every combination.
| Stem \ Branch | 子 Zi | 丑 Chou | 寅 Yin | 卯 Mao | 辰 Chen | 巳 Si | 午 Wu | 未 Wei | 申 Shen | 酉 You | 戌 Xu | 亥 Hai |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 甲 Jia | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ |
| 乙 Yi | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ |
| 丙 Bing | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ |
| 丁 Ding | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ |
| 戊 Wu | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ |
| 己 Ji | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ |
| 庚 Geng | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ |
| 辛 Xin | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ |
| 壬 Ren | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ |
| 癸 Gui | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ | ✗ | ✓ |
Where the year pillar and the hour pillar go wrong is almost never the formula; it is the boundary.
| Year | Lichun (Beijing time) | Year pillar | Born after lichun |
|---|---|---|---|
| 2025 | 2025-02-03 22:10 | 乙巳 Yi Si | year pillar of 2025 |
| 2026 | 2026-02-04 04:02 | 丙午 Bing Wu | year pillar of 2026 |
| 2027 | 2027-02-04 09:46 | 丁未 Ding Wei | year pillar of 2027 |
Lichun is the moment the sun reaches 315 degrees of ecliptic longitude, and it is the boundary at which the year pillar changes. In 2025 lichun fell on 3 February at 22:10 while lunar new year was 29 January — six days apart, and the zodiac animal of anyone born between them follows lichun. This site carries a lichun table from 1900 to 2100.
True solar time is the second boundary: clock time is the mean solar time of an administrative zone, and 80 degrees east differs from the zone meridian by 160 minutes while 119 degrees east differs by 4 — the same clock reading can sit in different two-hour blocks. This site prints the correction in minutes by longitude and leaves the choice to you rather than quietly making it.
These are the questions specific to this page; broader conventions live on the methodology page.
Every enumerable component of ba zi has its own page here. Each page is computed by the same engine and can be checked item by item — none of it is a personality table.