TL;DR: A major period is a ten-year frame in a Tử Vi chart, starting from the Mệnh palace and moving through the palaces in order: Dương Nam and Âm Nữ go clockwise, Âm Nam and Dương Nữ go counterclockwise. The starting age of the first major period equals the number of the cục, counted by nominal age: Thủy nhị cục starts at age two, Mộc tam cục at three, Kim tứ cục at four, Thổ ngũ cục at five, Hỏa lục cục at six. When interpreting a major period, besides the stars in the palace, one must also use the can of the major period palace to fly the Tứ Hóa; for the can Canh in particular, there are variant Tứ Hóa tables among texts, so the same chart can yield different Kỵ paths depending on the table used. A major period is only a time frame for cross-checking with the natal chart, not a verdict on whether ten years will be good or bad.
What is a major period in Tử Vi?
A major period is one of the two main layers of fortune in a Tử Vi chart, alongside the minor period. If the natal chart, also called the fixed chart, describes the whole person, family, career, wealth and health of the native over a lifetime, then the major period divides that life into ten-year stretches. Each stretch is anchored to one of the twelve palaces, and that palace temporarily plays the role of the Mệnh (Life) palace for the whole decade.
In the interpretive tradition, fortune is described as the changes in luck, misfortune or ups and downs within a given span of time, and is divided into two kinds: major fortune and minor fortune. The terms "đại vận" and "đại hạn" in Vietnamese Tử Vi are often used interchangeably, both meaning the ten-year stretch. To read a specific year you must build an additional minor-period layer; to read a month you must build an additional monthly-period layer. The smaller the unit of time, the more factors must be weighed and the easier it is to go wrong.
Which palace does the major period start from, and which direction does it go?
The first major period always starts from the Mệnh palace of the natal chart. From there, each subsequent major period shifts to an adjacent palace, in a direction that depends on gender and the yin-yang of the birth year. The book Đẩu số tinh thành, volume 1, part 1, states the rule clearly: Yang Male and Yin Female go forward, Yin Male and Yang Female go backward, each palace governing ten years.
In other words, there are four groups of natives:
- Yang Male, that is a man born in a yang lunar year: goes forward, in turn from Mệnh to Phụ Mẫu, Phúc Đức, Điền Trạch and so on.
- Yin Female, that is a woman born in a yin lunar year: also goes forward like Yang Male.
- Yin Male, that is a man born in a yin lunar year: goes backward, from Mệnh to Huynh Đệ, Phu Thê, Tử Tức and so on.
- Yang Female, that is a woman born in a yang lunar year: also goes backward like Yin Male.
In Tử vi đẩu số Mệnh vận phân tích, Từ Tăng Sinh gives the case of a young lady born in the year Giáp Thìn; because she is a Yang Female, her major-period direction runs in reverse. The starting point of her first major period falls at roughly age 5 to 14; past the age of 14, the major-period palace moves to the Huynh Đệ palace, governing the ten years from 15 to 24. A similar sequence continues for the remaining eleven palaces.
At what age does the major period begin?
The starting age of the first major period is not always one, but equals the number of the cục (elemental configuration) of the Mệnh palace, counted in tuổi mụ (nominal age). The book Đẩu số tinh thành gives the example of Thủy nhị cục, where the first major period is at the Mệnh palace, from age 2 to 11; the second major period from 12 to 21; later periods extend by the same principle. From that starting number, each stretch adds ten years.
| Cục of the Mệnh palace | Starting age of the first major period (tuổi mụ) | First major period | Second major period |
|---|---|---|---|
| Thủy nhị cục | 2 | 2 to 11 | 12 to 21 |
| Mộc tam cục | 3 | 3 to 12 | 13 to 22 |
| Kim tứ cục | 4 | 4 to 13 | 14 to 23 |
| Thổ ngũ cục | 5 | 5 to 14 | 15 to 24 |
| Hỏa lục cục | 6 | 6 to 15 | 16 to 25 |
The table above is only the standard framework for the first and second major periods; from the third major period onward, simply add ten years to the previous marker. Note that most Vietnamese documents count in tuổi mụ, that is the lunar age plus one compared with the solar age. This is one of the points on which schools do not fully agree, and it will be discussed further below.
How to read a specific major period
When a major period enters a palace, that palace is treated as the Mệnh palace of those ten years. To interpret it, we do two things in parallel: examine the tam phương tứ chính (the three directions and four cardinal points) of the major-period palace, and examine the heavenly stem of the major-period palace.
As for the tam phương tứ chính, the major-period palace plays the main role, and the three trine palaces plus the opposition palace play a supporting role. The stars sitting in the major-period palace, the stars converging from the trine and opposition, and the stars flanking the palace, are all taken into account. The book Tử vi kinh nghiệm, lower volume, has a verse saying that if the three directions are full of malefic stars but meet Triệt, it can still be saved, while if all four directions are beautiful but meet Tuần, the beauty is lost. The meaning is that Triệt and Tuần can reverse the situation of a major period, in one direction or the other.
As for the heavenly stem of the major-period palace, this is a point that is often overlooked. The stem of the major-period palace differs from the birth-year stem, so it brings out its own set of Tứ Hóa (Four Transformations) for those ten years. Từ Tăng Sinh cites a chart in his book where the major period enters the Tý palace, around age 33 to 42. Here, the Tài Bạch palace of the major period sits at Canh Thân, causing Thiên Đồng Hóa Kỵ to fall into the Mệnh palace of the major period; at the same time, the Quan Lộc palace of the major period sits at Bính Thìn, causing Thiên Đồng Hóa Lộc to also fall into the Mệnh palace of the major period. A single star, Thiên Đồng, carries both Hóa Lộc and Hóa Kỵ, producing a situation both favorable and unfavorable within those very ten years. This is why one cannot simply read the stars already present on the natal chart and then draw a conclusion for the whole decade.
It should be made clear: the example above follows the Tứ Hóa table used by Từ Tăng Sinh's book Tử vi đẩu số Mệnh vận phân tích, where the stem Canh makes Thiên Đồng hóa Kỵ. The chart utility on the site, however, uses a table that lists Thái Âm hóa Kỵ for the stem Canh, so if the same chart is set up on the site, the Kỵ path from the Canh Thân palace will fall into the palace containing Thái Âm, and the situation of "one Thiên Đồng carrying both Hóa Lộc and Hóa Kỵ" no longer exists.
Why does the same major-period palace give different results?
The major-period palace by itself does not say whether things are good or bad. The book Tử vi đẩu số Mệnh vận phân tích stresses that the four chart layers, Bản Mệnh, Đại Hạn, Lưu Niên and Lưu Nguyệt, are linked in a layer-upon-layer controlling manner; if any link in the chain is broken, the final result cannot take shape. The same major-period palace, placed in two different natal charts, will tell two different stories.
One example recorded in Vietnamese Tử Vi documents: a person met a major period considered very poor, with the main star fallen and clashing with the Mệnh, yet went from nothing to success. According to the explanation offered, that major-period palace may lie within the trine of the birth year, or the Mệnh may have Tuần or Triệt removing the deadlock. This shows that one should not apply a rigid formula to every chart.
The book Tử vi kinh nghiệm, lower volume, also has noteworthy pairings between major and minor periods: ten bad years meeting one good year is only average; ten good years meeting one bad year is less bad; ten good years meeting a good year is prosperity; ten bad years meeting a bad year is very arduous. This is a way of reading by proportion, not by adding and subtracting good and bad stars.
A fictional example chart
To picture how it moves, let us build a hypothetical chart: a man born in a yang lunar year, that is a Yang Male, with the Mệnh palace at Dần, and the cục being Thổ ngũ cục.
Because he is Yang Male, the major period goes forward. Because it is Thổ ngũ cục, the starting age is 5.
| Major period | Palace | Age range (tuổi mụ) |
|---|---|---|
| First | Mệnh at Dần | 5 to 14 |
| Second | Phụ Mẫu at Mão | 15 to 24 |
| Third | Phúc Đức at Thìn | 25 to 34 |
| Fourth | Điền Trạch at Tỵ | 35 to 44 |
| Fifth | Quan Lộc at Ngọ | 45 to 54 |
Suppose the Quan Lộc palace at Ngọ has the stem Bính. When the fifth major period enters this palace, we take the stem Bính to fly the transformations, then see which palaces of the natal chart those transformations fall into, while also examining the tam phương tứ chính of the Ngọ palace. If the Ngọ palace has a main star in a fallen position but gathers many auspicious stars from the trine and opposition, the major period can still be workable. Conversely, if the main star is at its peak but all four sides are malefic stars, the beauty is broken.
This example is only to illustrate how it moves and how it is read. No real chart is built here, and no conclusion is drawn about any specific individual.
Where the schools disagree
There are at least three significant differences among schools and books.
The first is the marker for changing major periods. Most Vietnamese documents count in tuổi mụ, that is the lunar age plus one. But some interpret by the actual birthday, holding that the major period changes on the exact birthday rather than at the start of the lunar year. The book Đẩu số tinh thành states clearly that it is tuổi mụ, and most Vietnamese Tử Vi documents follow this way. The two approaches differ by roughly a few months to a year at each marker, enough to change the conclusion about an event that falls right on the crossover.
The second is the "lưu đại hạn" method of counting each year within the major period, common in Vietnamese books. Instead of examining only the whole ten-year block, one also counts year by year within that block to know which year is the focus. The book Tử vi kinh nghiệm, lower volume, has a section comparing major and minor periods in this way. The specific counting differs among books, and not every book records it the same way.
The third is the approach of the Tứ Hóa school. This school does not merely read the stars already present in the major-period palace, but rearranges the twelve major-period palaces into a new chart, then uses the stem of each palace in that new chart to fly the transformations. In Khâm Thiên Tứ Hóa, collection no. 1, there is a passage discussing that when a major period overlaps with the position of a Hóa Kỵ tied to a physical object, for instance real estate, then events related to real estate will occur in those ten years. This way of reading requires building an entire separate major-period board, not just looking at the sitting stars.
Variant Tứ Hóa for the stem Canh
Because the stem of a major-period palace can be Canh, this point deserves separate mention since it directly changes the set of Tứ Hóa used for the whole ten years.
The Tứ Hóa table by stem that the chart utility on the site currently uses lists for the stem Canh: Thái Dương hóa Lộc, Vũ Khúc hóa Quyền, Thiên Đồng hóa Khoa, Thái Âm hóa Kỵ. This is the widely transmitted version; Vương Đình Chi calls the "Dương Vũ Đồng Âm" version the transmitted one.
The book Đẩu số tinh thành, volume 1, in its Tứ Hóa placement table and its quick-memory mnemonic, records the stem Canh in the order Dương Vũ Âm Đồng, that is Thái Dương hóa Lộc, Vũ Khúc hóa Quyền, Thái Âm hóa Khoa, Thiên Đồng hóa Kỵ. Từ Tăng Sinh's book Tử vi đẩu số Mệnh vận phân tích follows this approach too, which is why the stem Canh makes Thiên Đồng hóa Kỵ as in the example above.
Vương Đình Chi, founder of the Trung Châu school, according to his own private transmission, records the stem Canh with Thiên Phủ hóa Khoa and Thiên Đồng hóa Kỵ, and cites a line in the Toàn Thư that Thiên Đồng at Hợi, for a person born in the year Canh, makes Thiên Đồng hóa Kỵ, hence a lower configuration, in order to keep Thiên Đồng hóa Kỵ standing.
What all versions share is that for the stem Canh, Lộc remains Thái Dương and Quyền remains Vũ Khúc. The difference lies only in Khoa and Kỵ. Therefore, when a document calls the site's table the "Trung Châu approach", that label is wrong: Vương Đình Chi's Trung Châu school uses Thiên Đồng hóa Kỵ, not Thái Âm hóa Kỵ. The stems Tân and Nhâm also have variants, but this round has no source specifying which stars change, so it is left open.
Has the site's Tứ Hóa table been changed according to the variants?
No. The Tứ Hóa table of the chart utility and the palace-connection thread on the site remain as currently used, by the decision of the coordinator on 26/09/2026. For the stem Canh specifically, the site's chart gives Thiên Đồng hóa Khoa and Thái Âm hóa Kỵ. Readers need to know this so that when comparing with books, any discrepancy is understood as coming from a different table, not from setting up the chart incorrectly.
It should also be added that the very way of starting a major period has been called into question. Some documents record that when checking many charts with unusual events, people found that applying a different starting method gave results that matched better; but some opinions hold that one cannot hastily reject the usual starting method, and must reflect further on many charts with clear events. This is an open question, with no common conclusion.
The major period is only a framework, not a verdict
The most important thing when reading a major period is to remember that it is a time frame for comparison, not a sentence for ten years. The same major-period palace, placed next to a solid natal chart, tells a very different story from being placed next to a weak one. The same set of stars, meeting Tuần or Triệt, changes direction. The same main star, depending on the palace stem, transforms into Lộc or Kỵ. And the same major period, placed within a sequence of adjacent major periods, takes on a different meaning, because the previous and the next major period can dissolve or aggravate each other.
Therefore, when you see a major period with many auspicious stars, you should not immediately conclude that those ten years will certainly be good. When you see a major period with many malefic stars, you should not immediately conclude that those ten years will certainly be bad. A responsible reading sets out the major-period palace, the converging stars, the palace stem and the related fortune layers, then leaves readers to compare it with their own real circumstances.
