Ziwei Notes › Basics
Getting Started
What actually happens between a birth time and a finished chart
1. What information is needed
Casting a chart requires at least four things:
- Year, month and day of birth (lunar or Gregorian — software converts between them)
- The hour of birth (two hours to a shi-chen, twelve in all) — the most important item and the easiest to misremember
- Sex (decides the direction of the decade cycle and the use of some stars)
- Place of birth (for converting longitude into true solar time, below)
Get the hour wrong and the whole chart shifts. The ancients had no clocks; their sense of the hour came from the sun's position.
Time is therefore the point where a chart must be most exacting.
2. True solar time and the Zi hour
True solar time
A watch shows Beijing time (mean solar time at 120° east), but the traditional arts use local true solar time.
Written as "9 a.m.", the sun's position in Urumqi and in Shanghai differs by nearly two shi-chen.
So casting usually applies two corrections: first by longitude (about 4 minutes per degree), then the equation of time.
The more precise the birthplace, the more reliable the correction. For births across time zones, convert to local time first.
The Zi hour
23:00–01:00 is the Zi hour, and it straddles two days. Two conventions are current:
- Late Zi (23:00–24:00): belongs to the night Zi of the same day, and the day pillar stays with that day — the choice of most programs.
- Early Zi (00:00–01:00): belongs to the Zi hour of the next day, with the following day's pillar.
Schools differ on this point; if born in that window, cast it both ways and see which fits experience better.
3. The five-element phase
The phase is fixed by the gan-zhi of the birth year (its na-yin) and decides two things:
which palace Zi Wei starts from, and the age at which the decade cycle begins.
| Phase | Cycle starts | Note |
|---|
| Water, 2nd | age 2 | Earliest start; change shows young. |
| Wood, 3rd | age 3 | Gradual growth; unfolds step by step. |
| Metal, 4th | age 4 | Contracts into shape; clear rules. |
| Earth, 5th | age 5 | Heavy and stable; late but lasting. |
| Fire, 6th | age 6 | Latest start; slow to warm, then strong. |
The starting age can also be derived from the Life Palace position together with the phase; formulas vary slightly between schools. The table gives the common reading.
4. Life Palace and Body Palace
Life Palace (Ming)
The Life Palace anchors the whole chart. The formula runs roughly: start at the Yin palace for the first lunar month, count forward to the birth month,
then start the Zi hour from that palace and count backward to the birth hour — where you land is the Life Palace.
Once it is fixed, the other eleven palaces follow in a fixed order.
Body Palace (Shen)
The Body Palace lodges in one of the twelve (Life, Wealth, Career, Travel, Marriage or Happiness), decided by the birth hour.
The ancients took the Life Palace as innate nature and the Body Palace as where one later lodges:
what a person is by birth is read in the Life Palace; where effort goes through life is read in the Body Palace.
The Life Palace is the factory setting, the Body Palace the long-term choice. When the two are not in the same place, one can often see the tension between nature and ambition.
5. Placing the stars
Once the Life Palace is settled, the stars are laid in by fixed order and rule — the old "an xing". Roughly in these batches:
- Zi Wei: starts from a fixed place according to the phase and the day of birth, landing in one of the twelve palaces.
- The Zi Wei series (Tian Ji, Tai Yang, Wu Qu, Tian Tong, Lian Zhen): placed at fixed intervals from Zi Wei's position.
- The Tian Fu series (Tian Fu, Tai Yin, Tan Lang, Ju Men, Tian Xiang, Tian Liang, Qi Sha, Po Jun): placed symmetrically against the Zi Wei series.
- Hour stars (Wen Chang, Wen Qu, Qing Yang, Tuo Luo and others): placed by the birth hour.
- Month, day and year stars (Zuo Fu and You Bi, Tian Kui and Tian Yue, Lu Cun and Tian Ma, Hong Luan and Tian Xi and others): placed by the gan-zhi of month, day and year.
- Year transformations: by the year's heavenly stem, four major stars receive Lu, Quan, Ke and Ji (see The Four Transformations).
Done by hand this means consulting a dozen tables — which is exactly the part most fully replaced by software.
The tool on this site and the online calculator write these rules as code, so a chart can be recast and checked again.
6. Decade and yearly cycles
| Cycle | How it moves | Use |
|---|
| Decade (da xian) | One palace per ten years, starting from the Life Palace at the phase's starting age and moving with or against the order | The broad climate and theme of a ten-year stretch. |
| Yearly count (xiao xian) | One palace per year, started from the year branch | The emphasis of the year, read together with the decade and the year star. |
| Year star (liu nian) | The palace where the year's tai sui sits; read the year stars and year transformations | What is triggered in a specific year. |
| Month and day | Subdivided the same way | Finer timing; usage varies by school. |
The static chart says "what"; the cycles say "when".
What is called the timing of an event is usually the year found where these layers of time overlap.
7. Glossary
| Term | Meaning |
|---|
| San fang si zheng | The palace itself + its two trine palaces + the opposite palace — the four positions that must be weighed. |
| Opposite palace | The palace directly facing, six places away; surface and lining to each other. |
| Empty palace | A palace with none of the fourteen major stars; usually read through its opposite. |
| Miao / wang / li / xian | Grades of a star's brightness: bright stars act, fallen stars cannot. |
| Pattern | A named fixed combination of stars, such as "Sha Po Lang" or "Ji Yue Tong Liang". |
| Self-change | A palace's own stem transforming the star in that palace: the palace's own attitude. |
| Flying change | A palace's stem transforming a star in another palace: the pull between two palaces. |
| Timing | The window in which a matter may occur, usually derived from overlapping decade and year transformations. |
| Twelve year spirits | Sui Jian, Hui Qi, Sang Men, Guan Suo, Guan Fu, Xiao Hao, Da Hao, Long De, Bai Hu, Tian De, Diao Ke, Bing Fu — laid out by the year branch, used for the small events of a year. |
8. Common mistakes
- Supposing that more stars means better: fallen lucky stars lose to one bright star; weigh strength before counting.
- Judging from a single point: concluding from one palace or one star is the most common bias; palaces must be read against each other.
- Taking terms as verdicts: pattern names are labels; the same pattern can play out entirely differently in different lives.
- Ignoring the time correction: without true solar time, and without distinguishing early and late Zi, a chart may be off by a whole palace.
- Substituting it for professional judgement: for health, legal and financial matters, always rely on qualified professionals.
On health: the constitutional description in a chart belongs to a traditional cultural framework. For any physical complaint, see a doctor — this cannot replace diagnosis or treatment.