Free tool
Bát Tự chart
A Bát Tự chart turns the birth date and hour into eight stem and branch characters, with hidden stems, Ten Gods and ten-year luck pillars. The auxiliary stars are where books differ most: the Heavenly Noble of the stem Canh and the Yang Blade of yin stems each have more than one reckoning. The same chart can therefore carry a star on one site and not on another.
Casts a full Four Pillars chart with hidden stems, Ten Gods, Na Yin, the twelve stages, nine auxiliary stars, ten luck pillars, the conception pillar and the life palace. Every step is shown, and each contested convention is stated.
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What does a Bát Tự chart contain, and in what order is it read?
A Bát Tự chart, also called the Four Pillars, holds four stem and branch pairs for the year, month, day and hour of birth, eight characters in all. The day stem is the day master and stands for the person; every other stem is named by its five-element and yin-yang relation to the day master, giving the Ten Gods such as Direct Officer, Indirect Wealth and Eating God.
Each branch also holds one to three hidden stems: the strongest is the main qi, the others the middle and residual qi. Much of Tử Bình reasoning rests on hidden stems more than on the eight visible characters, so the chart here lists the hidden stems and their Ten Gods under every pillar, along with the Na Yin and the day master's stage in the twelve-stage cycle at that branch.
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, so two people born on the same day at different hours can enter their luck pillars months apart.
Auxiliary stars are looked up from the day stem, the year stem, or the Three Harmony group of the year and day branches. This is where books differ most: the Heavenly Noble for the stem Canh, the Yang Blade for yin stems and the lookup basis of the Peach Blossom each have more than one reckoning, and the page states its choice under every star.
Birth time is read as Vietnam time. The month pillar turns at a solar term rather than at the first of the lunar month, the year pillar turns at Lập Xuân, and the day pillar turns at 23:00, the start of the Tý hour. Anyone born close to those points should check the birth time before comparing with another chart.
| 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 are cast from the birth date and hour, but they are separate systems. Bát Tự reads eight stem and branch characters and the five-element relations among them; Tử Vi places over a hundred stars on twelve palaces. The two charts of one person do not convert into each other, and stars sharing a name, such as Văn Xương, are not placed by the same rule.
Why do my luck pillars run backward?
Because the direction depends on gender and on whether the year stem is yang or yin: 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 year stem is that of the year pillar, which turns at Lập Xuân, so someone born early in the solar year before Lập Xuân carries the previous year's stem.
The starting age here differs from my book. Which is right?
Usually both are right by their own convention. The page counts the days from birth to the nearest solar term to the minute, turns three days into one year, and gives the age counted from the birth date. Books using lunar age show one year more, and hand tables often round to the day or double hour, which shifts the result by a few months.
Why do the middle and residual qi of Thìn, Tuất, Sửu and Mùi differ from my table?
Because two naming schemes exist while the stems themselves are the same. The page follows the monthly command scheme: in Thìn, Quý is the middle qi because Water is stored there, and Ất is the residual qi left over from the Mão month. Many printed tables name them by print order and so swap the two labels. The Ten God of each hidden stem does not change.
Do the auxiliary stars decide whether a chart is good or bad?
No. In Tử Bình the auxiliary stars are a secondary layer; the chart's structure and the balance of the five elements among the eight characters carry the weight, and quite a few practitioners barely use these stars. The page lists nine common ones with their lookup basis so you can compare with a book, and draws no conclusion from them.
Is the chart still usable without a birth hour?
Partly. The year, month and day pillars and the luck pillars can still be cast, but without the hour pillar two characters are missing, the life palace cannot be found, and the auxiliary stars are checked on three pillars only. 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 sum of the birth month and hour numbers, counting Dần as 1, with its stem by the Five Tigers rule from the year stem. Both are supplements some schools consult; neither replaces the four pillars.
Is this result professional advice?
No. The chart is a calendar reckoning under one school's conventions, not scientifically verified, and it does not replace medical, legal or financial advice.