Five elements (wu xing)

The generating and overcoming cycles

Han writers put the phases in two orders, Littlejohn writes. In the generating cycle (相生 xiāngshēng) wood produces fire, fire produces earth, earth produces metal, metal produces water and water produces wood. In the overcoming cycle (相克 xiāngkè) wood conquers earth, earth conquers water, water conquers fire, fire conquers metal and metal conquers wood. The overcoming order was a theory of history: a dynasty ruling by water could expect to be replaced by one ruling by earth. The Han was thought to rule by fire, the red phase, and the Yellow Turban rebels of AD 184 set yellow against red.

The Huainanzi (139 BC) gives each phase a direction, a season, a planet, an animal and a pair of heavenly stems: wood is the east and spring, with the Azure Dragon and the stems jiǎ and yǐ; fire is the south and summer, with the Vermilion Bird and bǐng and dīng; earth is the centre, with the Yellow Dragon and wù and jǐ; metal is the west and autumn, with the White Tiger and gēng and xīn; water is the north and winter, with the Dark Warrior and rén and guǐ.

Heavenly stems, earthly branches and the sixty-year cycle

The Chinese calendar names years with two signs. The ten heavenly stems (天干 tiāngān) are jiǎ, yǐ, bǐng, dīng, wù, jǐ, gēng, xīn, rén and guǐ; the twelve earthly branches (地支 dìzhī) are zǐ, chǒu, yín, mǎo, chén, sì, wǔ, wèi, shēn, yǒu, xū and hài. Each stem is paired with a branch in turn, starting with jiǎzǐ and ending with guǐhài, and the Hong Kong Observatory notes that the cycle repeats every sixty years. The stems began, Japan’s National Diet Library explains, as names for counting days in groups of ten, and the branches as names for the order of the twelve months; the animals were attached to the branches later. The National Astronomical Observatory of Japan finds stem-branch dates on Shang oracle bones. Years were first named by the position of Jupiter, it says, but by the Later Han they were counted by simply running through the sixty pairs, as they still are.

Since stems and branches advance together, a stem returns every ten years, a branch every twelve and the same pair every sixty. 1966 and 2026 are both bǐngwǔ (丙午) in the Observatory’s tables: Fire and the Horse. That is why there is a Fire Horse year only once a lifetime, and why each animal comes round with five different elements.

Which element is a year?

The phases are carried by the stems, two each, yin and yang. The Huainanzi gives the pairs to the phases; in Japan, the National Astronomical Observatory and the National Diet Library explain, yin and yang became the “elder” (e) and “younger” (to) brother of each element, so that 丙 is read hinoe, “elder brother of fire”. Because the cycle lines up with the decade, the last digit of the Western year gives the stem.

The element belongs to the Chinese year, which begins at Lunar New Year, so someone born in January or early February takes the stem of the year before: the Fire Horse year began on 17 February 2026, and 2026 births before that date fall in the Wood Snake year. Calendars disagree on the changeover. The Hong Kong Observatory, which compiles Hong Kong’s calendar, changes the stem and branch on the first day of the first lunar month, as does the national standard China issued in 2017; fortune tellers, the Observatory notes, tend to change it at the solar term Spring Commences (4 February in 2018).

Elements in Chinese astrology

Chinese astrology gives each sign one or more of the five elements and a yin or yang energy, Littlejohn writes, and its lore holds that the signs and energies a person is born under shape their life and character: a wood person, in that lore, is strong and self-reliant, linked with the east and spring, and favours blue and green.