What Are the 12 Zodiac Animals? Meaning and How to Calculate Age by Earthly Branches

What are the 12 zodiac animals and where do they come from?

The 12 zodiac animals is the folk name for the twelve Earthly Branches in the East Asian stem-branch system: Tý (Rat), Sửu (Buffalo), Dần (Tiger), Mão (Cat; the Chinese calendar uses the Rabbit), Thìn (Dragon), Tỵ (Snake), Ngọ (Horse), Mùi (Goat), Thân (Monkey), Dậu (Rooster), Tuất (Dog) and Hợi (Pig). Each animal is tied to one Branch, used to mark years, months, days and hours. Combined with the ten Heavenly Stems (Giáp, Ất, Bính, Đinh, Mậu, Kỷ, Canh, Tân, Nhâm, Quý), they form a 60-year cycle commonly called the lục thập hoa giáp (sixty-year cycle).

The exact origin of this system is still debated, with most theories linking it to ancient calendrical and astronomical knowledge in East Asia. What is certain is that the 12 zodiac animals have been deeply embedded in Vietnamese cultural life for many centuries, shaping how people name ages, choose days, consider directions and even view human character. It should be stressed that this is traditional knowledge of a reference nature, not verified by modern science, and so it should not be treated as the sole basis for deciding major matters.

Why is the stem-branch cycle exactly 60 years long?

Because a stem and a branch can only pair when they share the same polarity, yin or yang. Among the ten stems, the yang stems are Giáp, Bính, Mậu, Canh, Nhâm; the yin stems are Ất, Đinh, Kỷ, Tân, Quý. Among the twelve branches, the yang branches are Tý, Dần, Thìn, Ngọ, Thân, Tuất; the yin branches are Sửu, Mão, Tỵ, Mùi, Dậu, Hợi. Yang stems pair only with yang branches, yin stems only with yin branches, so the number of pairs comes to 60 rather than 120. That is why the sixty-year cycle closes after 60 years.

Why is the first lunar month the month of Dần?

The three dynasties of Hạ, Thương and Chu each began the year in a different month. The Hạ dynasty took the month of Dần as the opening month of the year, the Thương dynasty took the month of Sửu, and the Chu dynasty took the month of Tý. The lunar calendar today follows the Hạ calendar, so the first month corresponds to the month of Dần. Hoàng Xuân Hãn's book Lịch và lịch Việt Nam also cross-checks these markers when discussing the origins of the calendar.

A summary table of the relationship groups among the twelve Earthly Branches as conceived in folk belief.

What does each zodiac animal represent in daily life?

In folk belief, each animal stands for a set of qualities and a particular time window in the day. This assignment of hours reflects the agricultural and natural rhythms of earlier generations.

As for character, folk tradition often assigns each zodiac year some broad traits: people born in the year of the Rat are seen as quick-witted and good with people; the year of the Buffalo as steadfast and hardworking; the year of the Tiger as brave and fond of leading; the year of the Cat as gentle and refined; the year of the Dragon as strong with leadership qualities; the year of the Snake as wise and discreet; the year of the Horse as passionate and freedom-loving; the year of the Goat as calm and emotionally rich; the year of the Monkey as clever and flexible; the year of the Rooster as principled and disciplined; the year of the Dog as loyal and straightforward; the year of the Pig as sincere and fond of a peaceful life. These are descriptions rooted in cultural convention, not fixed traits of any individual.

What should be kept in mind when calculating age by Earthly Branch?

Zodiac age is determined by the lunar year, beginning at Tết Nguyên Đán (the lunar new year) rather than 1 January on the solar calendar. This is where many people go wrong, especially those born around January or February on the solar calendar, since that point may still fall in the previous lunar year. In addition, some traditions mark the change of year at the Lập Xuân solar term in the solar-term calendar, which means people born near Tết can fall under two different zodiac signs depending on the method used.

When speaking of age, folk tradition distinguishes between tuổi âm (lunar age) and tuổi dương (mụ age), that is, lunar age plus one. Understanding the birth year, birth month and the timing of Tết in that year helps determine the correct zodiac animal. For purposes such as checking compatibility for marriage, choosing a day for groundbreaking or choosing the year to have a child, earlier generations also cross-checked the stem-branch of the year, month, day and hour of birth, not just the zodiac animal of the year.

How do you calculate the stem and branch of a year?

You can calculate quickly from the number of the year. The stem follows the final digit: 0 is Canh, 1 is Tân, 2 is Nhâm, 3 is Quý, 4 is Giáp, 5 is Ất, 6 is Bính, 7 is Đinh, 8 is Mậu, 9 is Kỷ. The branch follows the remainder when the year is divided by 12: remainder 0 is Thân, 1 is Dậu, 2 is Tuất, 3 is Hợi, 4 is Tý, 5 is Sửu, 6 is Dần, 7 is Mão, 8 is Thìn, 9 is Tỵ, 10 is Ngọ, 11 is Mùi. For example, the year 1788: it ends in 8, so the stem is Mậu, and it is divisible by 12, so the branch is Thân, making it the year Mậu Thân, the very year Quang Trung ascended the throne. This rule must be applied to the lunar year, so anyone born before Tết must use the previous year.

What are tam hợp, lục hợp, tứ hành xung and lục hại?

These four concepts form a web of relationships among the Earthly Branches, and they are the most explored part of any discussion of the 12 zodiac animals.

Tam hợp are groups of three zodiac animals sharing the same element and supporting one another, in four groups: Thân - Tý - Thìn (Water frame); Hợi - Mão - Mùi (Wood frame); Dần - Ngọ - Tuất (Fire frame); Tỵ - Dậu - Sửu (Metal frame). Folk belief holds that people within the same tam hợp group find it easy to sympathise with each other and to support one another in work and marriage.

Lục hợp are six pairs of Earthly Branches in yin-yang harmony: Tý - Sửu, Dần - Hợi, Mão - Tuất, Thìn - Dậu, Tỵ - Thân, Ngọ - Mùi. These pairs are seen as naturally compatible, each making up for what the other lacks.

Tứ hành xung are four zodiac animals forming two pairs in direct clash: Tý - Ngọ - Mão - Dậu and Thìn - Tuất - Sửu - Mùi, along with Dần - Thân - Tỵ - Hợi. These are the groups said to be prone to friction over views and pace of life.

Lục hại are six pairs in hidden clash: Tý - Mùi, Sửu - Ngọ, Dần - Tỵ, Mão - Thìn, Thân - Hợi, Dậu - Tuất. Unlike outright clash, lục hại is usually described as slow-burning disagreement that is hard to notice at once.

It should be stressed that all of these relationships belong to the realm of traditional knowledge and are of a reference nature. They do not determine the success or failure of a relationship or a plan; they are simply one perspective that earlier generations used for extra consideration.

Why does Tý stand first among the 12 zodiac animals?

Tý stands first because legend tells that in a race organised by the Jade Emperor, the rat rode on the buffalo's back and, near the finish line, jumped down ahead of it, so it was placed first while the buffalo came second. This story is only a later tale. Earthly Branches were already used to record days as far back as the Shang dynasty oracle bones, while attaching animals to each branch came much later. The book Thuật số Lạc Thư (Kỳ Môn Độn Giáp nguyên thủy) also records how earlier generations used the images of twelve animals to make the twelve branches easier to remember, showing that this is a layer of meaning added afterwards.

Why does Vietnam use the Cat instead of the Rabbit?

There is still no definitive conclusion, but two hypotheses are commonly mentioned. The first is based on agricultural life: the Vietnamese grow wet rice, rats are a scourge of the harvest, and cats catch rats, so cats were valued, while rabbits had little connection to Vietnamese rice-field life. The second is based on pronunciation: the character Mão sounds close to the word "mèo" (cat), so when it entered Vietnam it shifted to the cat. Both are hypotheses, and they are not mutually exclusive.

Why does the same zodiac animal have so many different interpretations?

One interesting point is that the same zodiac animal can be described differently depending on the context: in Tử Vi (Vietnamese astrology), in phong thuỷ (feng shui), in choosing auspicious days, or in folk literature. The year of the Dragon, for instance, is seen both as a mark of authority and as something that can be mentioned for hot temper and arrogance. This difference is not a contradiction; it reflects the many-layered meaning of a cultural symbol.

Beyond that, the naming of zodiac animals also differs between cultures. In Vietnam, the fourth animal is Mão (Cat), while many other places use the Rabbit. This is one of the points showing that the 12 zodiac animals are not a fixed system, but one localised from region to region.

How should the 12 zodiac animals be understood correctly?

The sensible approach is to see the 12 zodiac animals as part of cultural heritage and folk knowledge, helping us understand how earlier generations observed nature, organised time and built social relationships. It is not a tool for certain prediction about wealth, health or marriage. Checking ages, choosing days and choosing directions should be treated as a source of spiritual reference, alongside decisions based on reason, real circumstances and personal responsibility.

When exploring each smaller branch in more depth, such as tam hợp, lục hợp, tứ hành xung, lục hại or the character of each zodiac animal, readers will find a rich system with its own logic and many layers of meaning. Understanding its traditional nature correctly makes looking things up more interesting and more useful, instead of turning it into pressure or prejudice.

Articles in the Zodiac Animals topic

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• Ox - Horse Harm: The Six Harm Pair in the Chinese Zodiac and a Detailed Perspective
• Dần - Ngọ - Tuất Triple Harmony (Fire Group): The Triple Harmony Groups in the 12 Zodiac Animals
• Harmony Triangle of Pig - Cat - Goat (Wood Element): Exploring the Zodiac Compatibility Group
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• The Meaning of the Four Clashing Signs Ty - Ngo - Mao - Dau in Eastern Folk Belief
• Character traits of people born in the year of the Tiger in folk belief
• Character traits of people born in the year of the Rooster in folk belief
• Character traits of people born in the year of the Pig in folk belief
• Character traits of people born in the year of the Cat in folk belief
• Character traits of people born in the year of the Goat in folk belief
• Character traits of people born in the year of the Horse in folk belief
• Character traits of people born in the year of the Buffalo in folk belief
• Character traits of people born in the year of the Monkey in folk belief
• Character traits of people born in the year of the Dragon in folk belief
• Character traits of people born in the year of the Dog in folk belief
• Character traits of people born in the year of the Rat in folk belief
• Character traits of people born in the year of the Snake in folk belief