The 60-Year Cycle

The sexagenary cycle, known in Chinese as Liùshí Jiǎzǐ (六十甲子), is a system of counting years that has been central to Chinese timekeeping for over two thousand years. It combines two sequences — the Ten Heavenly Stems and the Twelve Earthly Branches — to produce a repeating cycle of exactly sixty unique year names. The earliest confirmed use of this system dates to the Shang Dynasty (c. 1600–1046 BCE), where oracle bone inscriptions used stem-branch pairs to record days. By the Han Dynasty, the cycle had become the standard method for naming years, months, days, and even hours across East Asia.

The Ten Heavenly Stems (Tiāngān, 天干) are an ordered sequence of ten symbols: Jiǎ (甲), Yǐ (乙), Bǐng (丙), Dīng (丁), Wù (戊), Jǐ (己), Gēng (庚), Xīn (辛), Rén (壬), and Guǐ (癸). Each pair of consecutive stems corresponds to one of the Five Elements — Wood, Fire, Earth, Metal, and Water — with the first stem in each pair being Yang and the second being Yin. For example, Jiǎ is Yang Wood and Yǐ is Yin Wood. The stems are believed to represent heavenly energy and the cyclical flow of cosmic forces. In practice, the element associated with a stem colors the character of the year it governs, adding a layer of meaning beyond the animal sign alone.

The Twelve Earthly Branches (Dìzhī, 地支) are: Zǐ (子), Chǒu (丑), Yín (寅), Mǎo (卯), Chén (辰), Sì (巳), Wǔ (午), Wèi (未), Shēn (申), Yǒu (酉), Xū (戌), and Hài (亥). Each branch is linked to one of the twelve zodiac animals — Rat through Pig — and also to a two-hour period of the day, a compass direction, and a month of the traditional calendar. The branches are thought to represent earthly energy and the tangible manifestations of time on the physical world. The pairing of a branch with its zodiac animal reflects qualities observed in nature: the Rat's activity at midnight corresponds to the Zi hour (11 pm–1 am), while the Horse's midday vigor matches the Wu hour (11 am–1 pm).

The sixty-year cycle is created by pairing the first stem with the first branch (Jiǎ Zǐ, 甲子), then advancing both sequences by one position for each successive year. Because the stems cycle every 10 and the branches cycle every 12, the least common multiple is 60 — meaning it takes exactly sixty years before the same stem-branch combination recurs. Importantly, Yang stems always pair with Yang branches and Yin stems with Yin branches, which is why only 60 of the theoretical 120 combinations actually occur. Each year in the cycle carries a unique combination of animal sign and elemental energy. For instance, 1924 is Jiǎ Zǐ (Wood Rat), 1925 is Yǐ Chǒu (Wood Ox), and 1926 is Bǐng Yín (Fire Tiger). The current cycle began in 1984 with another Jiǎ Zǐ year.

The sexagenary cycle remains deeply embedded in Chinese culture and daily life. It is the foundation of the traditional Chinese calendar and forms the basis for Bazi (八字) astrology, also known as Four Pillars of Destiny, which uses the stem-branch combinations for the year, month, day, and hour of birth to map a person's fate. The cycle also plays a role in feng shui, traditional medicine, and agricultural planning. In everyday culture, a person's 60th birthday holds special significance — it marks the completion of one full cycle and is celebrated as a symbolic rebirth. Many Chinese holidays and auspicious dates are determined using this system. The cycle has spread throughout East Asia: Japan, Korea, and Vietnam all adopted variations of the sexagenary system, and it continues to be used alongside the Gregorian calendar in official and ceremonial contexts.

The table below lists all sixty year designations in order, starting from 1924 (Jiǎ Zǐ). Each row shows the cycle number (1–60), the romanized stem-branch name, the Chinese characters, the corresponding Gregorian year, the zodiac animal, and the governing element. To find any year's designation, you can also calculate: subtract 1924 from the year, divide by 60, and use the remainder to look up the position in the cycle. For years before 1924, add multiples of 60. The next complete cycle begins in 1984 and runs through 2043. Since each animal sign appears five times in the cycle (once with each element), a Wood Rat year (1924, 1984) has different qualities from a Fire Rat year (1936, 1996) or a Water Rat year (1972, 2032).