Bát Tự chart
Cast your Bát Tự (Four Pillars) chart from your birth date, birth hour and sex. You get the eight stem and branch characters, a five-line plain-language summary, the ten-year luck pillars with their start years, and every step of the working so you can check it. Without a birth hour you still get three pillars.
Where this comes from
The four pillars of year, month, day and hour set up under the conventions of Tử Bình. The pillars are calendar computations: the year pillar turns at Lập Xuân, the month pillar follows the solar terms, the day pillar turns at 23:00. Hidden stems, the Ten Gods, auxiliary stars and luck pillars are the school's lookup rules; where the books differ is stated under each item.
Clock time in Vietnam time. The minute only matters near a solar term boundary or 23:00, and shifts the luck starting age by a few days.
Classical allusion
“Có thờ có thiêng, có kiêng có lành.”
Translation: Worship and it answers; keep the taboos and you stay well.
Vietnamese proverb
Next
Tử Vi chart
Bát Tự reads four pillars and the elements. The Tử Vi chart is a different system, placing 14 main stars in 12 palaces, with a plain-language summary.
Open Tử Vi chartWhere the schools differ
When the year turns over
2 more
When the month turns over
Which clock the birth time uses
What no one has shown
No study has shown that the eight characters of a birth date and hour correspond to a person's character or life. The machine only guarantees that the four pillars are set up correctly and the stated rules are applied correctly.
Read on
Ask Nhật Nguyệt AI
Learn more
What is in a Bát Tự chart, and in what order should you read it?
Bát Tự, also called the Four Pillars, writes your birth year, month, day and hour as four stem-and-branch pairs, eight characters in all. The stem of your birth day is the day master and stands for you. Every other character is named by its relation to the day master, giving ten roles (the Ten Gods) such as Direct Officer, Indirect Wealth and Eating God.
The usual reading order: who the day master is; which element the eight characters lean towards; whether the birth month supports the day master; which role repeats most; and the ten-year stretch you are in. The quick summary at the top follows those five steps.
Each branch also hides one to three stems, called hidden stems. The strongest is the main qi, the others the middle and residual qi. The chart lists the hidden stems and their roles under each pillar.
Luck pillars divide a life into ten-year stretches, starting from the month pillar. A man born in a yang-stem year and a woman born in a yin-stem year run forward; the other two cases run backward. The starting age counts the days from birth to the nearest solar term in that direction, three days to a year.
Auxiliary stars are looked up from tables, and this is where books differ most: the Heavenly Noble for the stem Canh, the Yang Blade for yin stems and the base for the Peach Blossom each have more than one method. The page notes its choice under each star.
Birth time is read as Vietnam time. The month pillar turns at a solar term, the year pillar at Lập Xuân, and the day pillar at 23:00, the start of the Tý hour. Some masters keep the old day until midnight, so anyone born between 23:00 and midnight may see a different day pillar elsewhere.
| Branch | Main qi | Middle qi | Residual qi |
|---|---|---|---|
| Tý | Quý (Water) | none | none |
| Sửu | Kỷ (Earth) | Tân (Metal) | Quý (Water) |
| Dần | Giáp (Wood) | Bính (Fire) | Mậu (Earth) |
| Mão | Ất (Wood) | none | none |
| Thìn | Mậu (Earth) | Quý (Water) | Ất (Wood) |
| Tỵ | Bính (Fire) | Canh (Metal) | Mậu (Earth) |
| Ngọ | Đinh (Fire) | Kỷ (Earth) | none |
| Mùi | Kỷ (Earth) | Ất (Wood) | Đinh (Fire) |
| Thân | Canh (Metal) | Nhâm (Water) | Mậu (Earth) |
| Dậu | Tân (Metal) | none | none |
| Tuất | Mậu (Earth) | Đinh (Fire) | Tân (Metal) |
| Hợi | Nhâm (Water) | Giáp (Wood) | none |
Frequently asked questions
How is Bát Tự different from Tử Vi?
Both start from the birth date and hour, but they are separate systems. Bát Tự reads eight stem-and-branch characters and the element relations between them; Tử Vi places over a hundred stars in twelve palaces. One person's two charts do not convert into each other.
Why do my luck pillars run backward?
The direction depends on sex and the year stem: men born in yang-stem years and women born in yin-stem years run forward; the other two run backward. The year stem changes at Lập Xuân, so someone born early in the Gregorian year before Lập Xuân takes the previous year's stem.
My book gives a different starting age. Which is right?
Usually both are right by their own convention. The page counts the days to the solar term to the minute, turns three days into a year and gives your actual age. Books using lunar age show one year more, and hand tables often round, which shifts things by a few months.
Why do the middle and residual qi of Thìn, Tuất, Sửu and Mùi differ from my table?
Because there are two naming schemes for the same stems. The page follows the monthly command scheme: in Thìn, Quý is the middle qi and Ất the residual qi. Many printed tables name them by print order and swap the two. Each hidden stem's role stays the same.
Do the auxiliary stars decide whether a chart is good or bad?
No. In Tử Bình the auxiliary stars are a secondary layer; the balance of the eight characters is the core, and quite a few practitioners barely use them. The page lists nine common ones with their lookup basis so you can compare with a book.
Is the chart still useful without a birth hour?
Partly. The year, month and day pillars and the luck pillars still work, but the two hour characters are missing and the life palace cannot be found. The starting age is reckoned from noon and may be off by up to four months.
What are the conception pillar and the life palace?
The conception pillar is the stem and branch of the month of conception: the month stem one step on and the month branch three steps on. The life palace is 14 minus the birth month and hour numbers (counting Dần as 1), with its stem by the Five Tigers rule from the year stem. Both are extras some schools use; neither replaces the four pillars.