TL;DR: The eight hạn in a year (bát hạn) are eight periods of trouble that folk belief holds may fall on a person each year: Huỳnh Tuyền, Tam Kheo, Ngũ Mộ, Thiên Tinh, Toán Tận, Thiên La, Địa Võng and Diêm Vương, usually mentioned with the nine destiny stars in the phrase dâng sao giải hạn. The book Tử Vi khảo luận names and describes each hạn but gives no method of calculation, and no old text is known to set out the whole system. It is a folk belief with no scientific evidence behind it.
What are the eight hạn in a year?
The eight hạn in a year (bát hạn) are eight "hạn", or periods of trouble, that folk belief holds may fall on a person in a given year: Huỳnh Tuyền (Hoàng Tuyền), Tam Kheo, Ngũ Mộ, Thiên Tinh, Toán Tận, Thiên La, Địa Võng and Diêm Vương. They are usually mentioned together with the nine destiny stars (Cửu Diệu), and form the second half of the familiar phrase "dâng sao giải hạn", making offerings to the stars to ward off the year's hạn.
The book Tử Vi khảo luận by Hoàng Thường and Hàm Chương says exactly this: besides the Cửu Diệu, the nine stars believed to govern each person every year, "there are also the bát hạn, the eight yearly hạn", and that is where the phrase about offerings to the stars comes from[1]. This is a folk belief; no old text is known to set out this eight-hạn system together with a method of calculation.
Which hạn make up the eight, and how is each described?
The table below summarises how Tử Vi khảo luận describes each hạn[1]. The last column is the book's wording, not something that has been verified.
| Order in the book | Hạn | The book describes it as |
|---|---|---|
| 1 | Huỳnh Tuyền (Hoàng Tuyền) | A heavy hạn, loss of money, danger to oneself |
| 2 | Tam Kheo | A minor hạn, possibly mild eye trouble and aches all over |
| 3 | Ngũ Mộ | A minor hạn but with loss of money and illness, especially in the elderly |
| 4 | Thiên Tinh | Trouble out of nowhere, quarrels, lawsuits, spending money |
| 5 | Toán Tận | A bad hạn for men: loss of money, illness, worry |
| 6 | Thiên La | A bad hạn, causing obsession and an unsettled mind |
| 7 | Địa Võng | Gossip and disputes, like Thiên Tinh but lighter |
| 8 | Diêm Vương | Very unfavorable for women, as bad as Toán Tận is for men; much distress |
These descriptions come from a modern Vietnamese Tử Vi book. Other books and regions may describe them differently, and there is no Chinese original to check against.
How are the eight hạn calculated?
In folk practice, the year's hạn is looked up by lunar age and sex. For the nine stars, Tử Vi khảo luận explains adding the two digits of one's age and reading a table, or "consulting the yearly Tử Vi books"; for the eight hạn, it only gives the names and descriptions, with no method of calculation[1]. Old almanac books do not even agree on the names of the hạn, as the table below shows.
The book Vạn sự bất cầu nhân has two other tables named after Hoàng Tuyền, "Ten positions of Hoàng Tuyền" and "Eight positions of Hoàng Tuyền", which place the positions on the eight trigrams, counting forward for boys and backward for girls[2]. The eight-position table has Hoàng Tuyền, Toán Tận, Tam Khâu, Tiểu Hỷ, Đại An, Tiểu Sát, Ngũ Mộ and Mạnh Cùng, and the book notes that meeting Hoàng Tuyền brings mourning, Tam Khâu serious illness, and Tiểu Sát something auspicious[2]. Four names match the eight hạn above, four are entirely different:
| Name | In the eight hạn (Tử Vi khảo luận) | In the eight positions of Hoàng Tuyền (Vạn sự bất cầu nhân) |
|---|---|---|
| Hoàng Tuyền (Huỳnh Tuyền) | Yes | Yes |
| Tam Kheo (Tam Khâu) | Yes | Yes |
| Ngũ Mộ | Yes | Yes |
| Toán Tận | Yes | Yes |
| Thiên Tinh | Yes | No |
| Thiên La | Yes | No |
| Địa Võng | Yes | No |
| Diêm Vương | Yes | No |
| Tiểu Hỷ | No | Yes |
| Đại An | No | Yes |
| Tiểu Sát | No | Yes |
| Mạnh Cùng | No | Yes |
The two are different systems, so the counting of the eight-position table cannot be used to work out the eight hạn.
How do the eight hạn relate to the destiny stars?
The Cửu Diệu and the bát hạn are spoken of together but kept apart. The Cửu Diệu are the nine destiny stars: La Hầu, Thổ Tú, Thủy Diệu, Thái Bạch, Thái Dương, Vân Hán, Kế Đô, Thái Âm, Mộc Đức. Tử Vi khảo luận lists the nine stars first and only then the eight hạn, as something that comes "in addition"[1]. According to the book, La Hầu for men and Kế Đô for women are years regarded as bad for each sex[1].
Can the eight hạn be trusted?
There is no scientific evidence that the eight hạn predict a person's fate, health or money. This is a folk belief belonging to faith and culture. Even Tử Vi khảo luận makes offering to the stars to ward off hạn conditional: "if one believes in the gods"[1].
A suggestion from Nhật Nguyệt: read the eight hạn as part of folk culture, to understand why many families go to the temple at the start of the year, not as a reason to worry or to decide a real matter by the name of the year's hạn.
