The Vietnamese zodiac: heavenly stems, earthly branches, nạp âm and compatible signs

When Vietnamese people ask "what year are you?", they are asking about your con giáp, the animal of your lunar birth year. Behind that simple question lies a calendar system thousands of years old, built from two interlocking cycles and the five elements. This guide explains the pieces.

Heavenly stems and earthly branches

The system combines two counting cycles:

• The ten heavenly stems (thiên can): Giáp, Ất, Bính, Đinh, Mậu, Kỷ, Canh, Tân, Nhâm, Quý. They come in pairs, one yang and one yin, for each of the five elements: Giáp and Ất are Wood, Bính and Đinh Fire, Mậu and Kỷ Earth, Canh and Tân Metal, Nhâm and Quý Water.
• The twelve earthly branches (địa chi): Tý, Sửu, Dần, Mão, Thìn, Tỵ, Ngọ, Mùi, Thân, Dậu, Tuất, Hợi, matched with the Rat, Buffalo, Tiger, Cat, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog and Pig.

Each year takes the next stem and the next branch at the same time. Since yang stems only ever meet yang branches, the pair repeats every 60 years rather than 120. That sixty-year cycle, starting at Giáp Tý, is why an elder's 60th birthday, the lễ lục tuần, is a full circle.

Working out a year's can chi

You can find the stem from the last digit of the Gregorian year:

For the branch, divide the year by 12 and look at the remainder: 0 Thân, 1 Dậu, 2 Tuất, 3 Hợi, 4 Tý, 5 Sửu, 6 Dần, 7 Mão, 8 Thìn, 9 Tỵ, 10 Ngọ, 11 Mùi. Take 1990: it ends in 0, so the stem is Canh, and 1990 divided by 12 leaves 10, so the branch is Ngọ. 1990 is a Canh Ngọ year, a Horse year.

Nạp âm: the element of your destiny

When people talk about their mệnh (destiny element), they usually mean the nạp âm element. The sixty years of the cycle are grouped in thirty consecutive pairs, and each pair carries a poetic image of one of the five elements, such as "Gold in the Sea" or "Lamp Fire". Some recent years:

The five elements interact in two classic cycles. In the generating cycle, Metal feeds Water, Water feeds Wood, Wood feeds Fire, Fire feeds Earth and Earth feeds Metal. In the controlling cycle, Metal cuts Wood, Wood breaks Earth, Earth dams Water, Water puts out Fire and Fire melts Metal.

Compatible and clashing animals

Folk tradition describes three kinds of relationship between the branches:

• Tam hợp (three harmonies): Thân, Tý, Thìn; Dần, Ngọ, Tuất; Hợi, Mão, Mùi; Tỵ, Dậu, Sửu. Animals in the same group are said to understand one another easily.
• Lục hợp (six pairings): Tý with Sửu, Dần with Hợi, Mão with Tuất, Thìn with Dậu, Tỵ with Thân, Ngọ with Mùi. These pairs are said to support each other quietly.
• Tứ hành xung (four-way clashes): Tý, Ngọ, Mão, Dậu; Dần, Thân, Tỵ, Hợi; Thìn, Tuất, Sửu, Mùi. The sharpest friction is between direct opposites, such as Tý and Ngọ.

These pairings are used for choosing business partners, wedding dates or who first crosses the threshold at Tết. They are traditions, not destiny: plenty of happy couples belong to clashing signs.

Why Vietnam has a Cat, not a Rabbit

China, Korea and Japan place the Rabbit at the fourth branch, but Vietnam has the Cat. No one knows for certain why. The most common explanation is linguistic: the branch Mão, also pronounced Mẹo, sounds very close to "mèo", the Vietnamese word for cat. Another theory points to farming life, where cats protecting the rice store were far more familiar than rabbits. The Vietnamese zodiac also keeps the water buffalo (trâu) for Sửu, a nod to its place in the rice fields.

The Tết boundary

The animal year begins at Tết, the lunar New Year, which falls between late January and mid-February, not on 1 January. Anyone born in January or early February should check the date of Tết in their birth year. Tết 2026 fell on 17 February, so a baby born on 10 February 2026 still belongs to the Ất Tỵ year, the Snake, with Phú Đăng Hỏa as their element. Only babies born from 17 February onwards are Bính Ngọ Horses. Some advanced systems, such as Four Pillars charts, start the year at Lập Xuân around 4 February instead, but popular tử vi follows Tết.