TL;DR: 2027 is the year Đinh Mùi (the Goat), with the nạp âm Thiên Hà Thủy, running from Tết on 6 February 2027 to just before Tết on 26 January 2028; Bát Tự changes the year at Lập Xuân, 8:42 on 4 February 2027. In the folk way of matching ages, on the zodiac axis parents of the Hợi, Mão and Ngọ ages are considered favorable and those of the Tý, Sửu, Thìn and Tuất ages unfavorable; on the nạp âm axis parents with Metal, Water or Wood are considered favorable and those with Earth or Fire unfavorable. The axes can contradict each other, and this is a cultural convention, not a scientific conclusion about health or destiny.
What year is 2027, and what is its nạp âm?
2027 is the year Đinh Mùi: stem Đinh, branch Mùi (the Goat). The pairs Bính Ngọ and Đinh Mùi share the nạp âm Thiên Hà Thủy, of the Water element. A nạp âm is the element assigned to each stem and branch pair in the sixty-year cycle, distinct from the element of the stem (Đinh is Fire) and of the branch (Mùi is Earth). The book Tử Vi khảo luận glosses the nạp âm of the Đinh Mùi age as the water of the river in the sky[1].
By the lunar calendar computed in Vietnam time, the Đinh Mùi year runs from Tết on 6 February 2027 to just before the Mậu Thân Tết on 26 January 2028. A child born in that span is a Mùi child in the folk way of counting age and in Tử Vi. Bát Tự uses Lập Xuân instead: the Đinh Mùi year pillar runs from 8:42 on 4 February 2027 to just before 14:30 on 4 February 2028. Because the two boundaries differ, a child born from 8:42 on 4 February to the end of 5 February 2027 is a Bính Ngọ child by the lunar year but has a Đinh Mùi year pillar, and a child born from 26 January 2028 to just before 14:30 on 4 February 2028 is a Mậu Thân child by the lunar year but still has a Đinh Mùi year pillar.
Which parents' birth years are compatible with a child born in 2027 Đinh Mùi according to the stems and branches?
The folk way of matching ages compares the child's birth-year branch with the father's and the mother's branch using four tables: tam hợp and lục hợp count as favorable, tứ hành xung and lục hại count as unfavorable. For the branch Mùi: Mùi is in the same tam hợp group as Hợi and Mão, forms a lục hợp with Ngọ, is in the same tứ hành xung group as Sửu, Thìn and Tuất, and forms a lục hại with Tý. The four branches Dần, Tỵ, Thân and Dậu belong to no combining or clashing group with Mùi. So by this reckoning, parents of the Hợi, Mão and Ngọ ages are considered favorable for a Mùi child, and parents of the Tý, Sửu, Thìn and Tuất ages are considered unfavorable.
On the stem side, the child's stem Đinh combines with the stem Nhâm (Đinh and Nhâm are one of the five combining pairs) and clashes with the stem Quý; with the other eight stems it neither combines nor clashes.
Besides these four tables, some books also consider hình, phá and lục xung: Sửu, Tuất and Mùi form a tam hình group, Tuất is in phá with Mùi, and Sửu clashes with Mùi in lục xung. The tables are separate conventions, so one pair of ages can combine in one table and clash in another.
The table below summarizes the relationship between the branch Mùi and the twelve branches under the four folk tables:
| Parent's branch | Relationship with Mùi | In the folk way of matching ages |
|---|---|---|
| Hợi | Tam hợp | Favorable |
| Mão | Tam hợp | Favorable |
| Ngọ | Lục hợp | Favorable |
| Tý | Lục hại | Unfavorable |
| Sửu | Tứ hành xung | Unfavorable |
| Thìn | Tứ hành xung | Unfavorable |
| Tuất | Tứ hành xung | Unfavorable |
| Dần | Neither combining nor clashing | Neutral |
| Tỵ | Neither combining nor clashing | Neutral |
| Thân | Neither combining nor clashing | Neutral |
| Dậu | Neither combining nor clashing | Neutral |
| Mùi | Same branch | Counted as neither combining nor clashing |
Which parents' nạp âm is compatible with the nạp âm Thiên Hà Thủy?
Besides the stems and branches, the folk way of matching ages also sets the element of the child's nạp âm (Water) beside the element of the father's and the mother's nạp âm. Metal generates Water, so parents with a Metal nạp âm (Hải Trung Kim, Kiếm Phong Kim, Bạch Lạp Kim, Sa Trung Kim, Kim Bạc Kim, Thoa Xuyến Kim) have an element that generates the child's, which counts as favorable. Parents with a Water nạp âm (Giản Hạ Thủy, Tuyền Trung Thủy, Trường Lưu Thủy, Thiên Hà Thủy, Đại Khê Thủy, Đại Hải Thủy) share the child's element, called level harmony, which also counts as favorable. Water generates Wood, so parents with a Wood nạp âm (Đại Lâm Mộc, Dương Liễu Mộc, Tùng Bách Mộc, Bình Địa Mộc, Tang Đố Mộc, Thạch Lựu Mộc) have an element generated by the child's, which also counts as favorable. Earth overcoming Water means the parent's element overcomes the child's, and Water overcoming Fire means the child's element overcomes the parent's; both directions count as unfavorable.
The ways of matching ages in circulation do not agree on which axis weighs more: some compare only the nạp âm element, some only the zodiac animal, some consider stem, branch and nạp âm together. Two axes can point in opposite directions: a Đinh Mùi child with a mother of the Giáp Tý age (Hải Trung Kim) is a lục hại pair on the zodiac axis, yet Metal generates Water on the nạp âm axis.
Why is the nạp âm Thiên Hà Thủy considered "water of the sky"?
Hiệp kỷ biện phương thư (book 1, section on nạp âm) records Đào Tông Nghi's explanation of the names of the sixty nạp âm. On this pair, Đào Tông Nghi writes: 丙午丁未天河水者丙丁屬火午為火旺之地而納音乃水水自火出非銀漢不能有也故曰天河水也. That is: Bính and Đinh belong to Fire, Ngọ is a place where Fire is at its peak, yet the nạp âm is Water; water that comes out of fire can only be the water of the Milky Way, hence the name Thiên Hà Thủy. This is a figurative explanation from the old authors, not a physical description.
Which parents' birth years should be given extra consideration?
In the folk way of matching ages, parents of the Tý age (lục hại with Mùi) and of the Sửu, Thìn and Tuất ages (same tứ hành xung group as Mùi) are considered unfavorable on the zodiac axis when having a child in a Mùi year. That is only one axis: for the same pair of ages, the stem axis and the nạp âm axis can be favorable. In reality, the relationship between parents and children is shaped by family circumstances, upbringing, health and living environment, which lie outside the scope of stems, branches or nạp âm.
No scientific research has proven a connection between the Can Chi birth year and the quality of family relationships or human health. The belief that a child's age "overcomes" a parent's age is a product of a cultural convention that no one has proven. Readers should treat this as cultural reference information, not use it to decide whether to have a child or to judge people.
Should one choose the year of a child's birth according to compatible birth years?
The book Việt Nam phong tục by Phan Kế Bính, in its section on choosing days and hours, records that the thing most avoided for a newborn is being born in the hour of kim xà thiết tỏa; a child born in that hour is hard to raise and needs a ritual of averting misfortune before it can be raised[2]. The book also records how that hour is reckoned from the year, month, day and hour of birth and from whether the child is a boy or a girl[2]. This custom is not about choosing the hour of birth; it is how people of old dealt with it after the child was born.
Vương Sung of the Eastern Han, in the chapter Biện túy (辨祟) of the book Luận hành, describes the belief that illness, death and imprisonment all come from breaking a taboo, from building, moving house or marrying without choosing an auspicious day or avoiding the forbidden year and month; then he writes: 如實論之，乃妄言也 (judged truthfully, this is idle talk)[3].
The book Tử Vi khảo luận by Hoàng Thường and Hàm Chương, in its discussion of applying Tử Vi to psychoanalysis, argues that the interpretive method of Tử Vi should have a considerable place in today's school of psychoanalysis; the same passage says that however talented one is, one cannot give birth to a child as one wishes[1].
The actual date and hour of birth are decided by the health of mother and child, as the doctor advises.
Nhật Nguyệt's suggestion
To look this up yourself, you need the lunar birth years of the father and the mother; anyone born in January or early February should check against the Tết date of that year. The Child's birth year by parents' ages tool compares each year with the father and with the mother on three axes, stem, branch and nạp âm, and keeps each axis separate without adding up scores. The result is a layer of cultural information; the mother's health, the family's circumstances and the way the child is raised are what decide having and raising a child.
Points to note when looking things up
When looking up compatible birth years, there are three points that are easily confused. First, the nạp âm of a birth year is not the same as the element of the stem and the element of the branch; for example, the year Đinh Mùi has a Fire stem and an Earth branch, but its nạp âm is Water. Second, the lunar age changes at Tết, not on 1 January, while Bát Tự changes the year at Lập Xuân; the boundaries for 2027 are given at the top of this article. Third, books may use the words "hợp", "khắc", "xung" and "hại" with differing degrees; one should not take a single concluding sentence as the standard for every case.
The way of examining compatible birth years by stems and branches is only one part of the Eastern metaphysical system, alongside Tử Vi, Bát Tự and phong thủy. Each discipline has its own way of reasoning and may give different results.
