What is Lục Thập Hoa Giáp?

The Sixty Jiazi is a cycle of 60 sexagenary combinations of Heavenly Stems and Earthly Branches used to number years, months, days and hours in traditional East Asian calendrics, each combination paired with a Na Yin Five Element.

Also called: 60 hoa giáp · chu kỳ 60 năm · 六十花甲

What is the Sixty Jiazi?

The Sixty Jiazi (六十花甲) is a cycle of 60 units formed by pairing the ten Heavenly Stems (Jia, Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren, Gui) with the twelve Earthly Branches (Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, Hai). Because a Stem and a Branch combine only when they share the same polarity (both yang or both yin), the number of possible combinations is the least common multiple of 10 and 12, namely 60. After 60 years the cycle returns to its starting point, which is why it is also called "one huajia" or "one full zodiac round".

Why is it called "huajia"?

The character "hua" (花, flower) conveys variety and interweaving, like flowers and leaves, alluding to the intricate interlacing of the 60 Stem-Branch combinations. The character "jia" (甲) is both the name of the first Stem and a word for "first" or "beginning". The phrase "huajia" is also used to refer to the age of 60, the age at which one completes a full Stem-Branch cycle. In traditional culture, celebrating a 60th birthday is an important milestone marking a complete cycle of life according to the Stem-Branch calendar.

Na Yin and its role in calendrics

Each successive Stem-Branch pair is assigned a "Na Yin" (納音), a name with a Five-Element quality, such as Sea Gold, Furnace Fire or Great Sea Water. Na Yin is not derived directly from a single Stem or Branch but follows an ancient rule. In calendrics, the Sixty Jiazi is used to record years, months, days and hours; in astrology, feng shui and date selection, the Na Yin of the birth year is often used to interpret a person's Na Yin Five Element.

Distinguishing it from easily confused concepts

The Sixty Jiazi should be distinguished from the Twelve Earthly Branches (the twelve zodiac animals) and the Ten Heavenly Stems. The Sixty Jiazi is the combination of both, not a separate set of symbols. It should also be distinguished from a "natal element" based on a single Stem or Branch: two people born in the same zodiac year may still have different Na Yin if their Stems differ. Furthermore, "one huajia" refers to a 60-year cycle, not to a century in the 100-year sense.

Note: this is traditional knowledge for reference only and has not been verified by science. Its applications in astrology, feng shui and date selection should be regarded as cultural heritage, not as a substitute for decisions based on scientific grounds.

Frequently asked questions

Is the Sixty Jiazi the same as 60 zodiac animals?

No. The Sixty Jiazi is 60 combinations of the 10 Heavenly Stems and 12 Earthly Branches, whereas "zodiac animal" usually refers only to the 12 Earthly Branches. Each year in the 60-year cycle has its own Stem-Branch combination, which does not repeat until the cycle ends.

Why is the Stem-Branch cycle 60 and not 120?

Because a Stem and a Branch can only pair when they share the same polarity (both yin or both yang). The number of possible pairs is the least common multiple of 10 and 12, which is 60. Pairing all 10 Stems with all 12 Branches arbitrarily would yield 120 pairs, but half of them are invalid under the yin-yang rule.

Is the Na Yin in the Sixty Jiazi a person's natal element?

Traditionally, the Na Yin of the birth year is often called the "Na Yin element" and used to interpret the Five Elements. However, this is a convention of traditional divination, not a biological or scientific attribute. Many schools also use the Stem, Branch, and the birth date and hour for a fuller reading.

Has a 60-year-old person completed one Sixty Jiazi cycle?

Yes, according to traditional age reckoning or Stem-Branch age. When 60 years have passed since birth, the Stem-Branch of that year matches the birth year's Stem-Branch, marking a full cycle. This underlies the custom of celebrating a 60th birthday in many East Asian cultures.

References

Hoàng Xuân Hãn, Lịch và lịch Việt Nam

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Nguồn: Nhật Nguyệt - https://nhatnguyet.org/en/tu-dien/luc-thap-hoa-giap