The twelve Earthly Branches (地支)

The twelve Earthly Branches are the second set of calendar signs. Most people know them as the twelve zodiac animals, but each branch also marks a two-hour period of the day, a month of the year and one of the five elements.

One set of twelve, used four ways

The branches count things that come in twelves. There are twelve years in the animal cycle, twelve months in a year, and twelve double-hours in a day. The same twelve signs label all of them, which is why a chart can describe a year, a month, a day and an hour with one vocabulary.

The animal names are the popular face of the branches: 子 is the Rat, 丑 the Ox, and so on to 亥, the Pig. The animals are a memory aid attached to the signs, in the same way the Heavenly Stems have pictures such as "tall tree" or "rain".

The twelve double-hours

Traditional timekeeping divides the day into twelve periods of two hours each, one per branch. The day begins with the 子 hour, which runs from 23:00 to 01:00 and so straddles midnight; the 午 hour, 11:00 to 13:00, sits around noon. Each period is named after its branch: the 卯 hour is early morning, the 酉 hour is dusk.

These hours are counted in local solar time in the classical method, which can differ from clock time by a few minutes to more than half an hour depending on where you are inside a time zone. Apps that calculate a chart usually correct for this from the birth city.

Branches, seasons and elements

The branches follow the year. 寅 and 卯 are the spring months and belong to Wood; 巳 and 午 are summer and belong to Fire; 申 and 酉 are autumn and Metal; 亥 and 子 are winter and Water. The four branches that close each season - 辰, 未, 戌 and 丑 - belong to Earth, the element of the turning points between seasons.

That is why the month of birth matters so much in chart reading: the month branch tells you which element was in season. A Wood stem born in a spring month is "in season" and is read as well supported; the same stem born in an autumn month, when Metal is in charge, is not.

Each branch also carries one to three stems inside it, called hidden stems. They are the reason a branch can lend support to more than one element. The details are a topic of their own, but the short version is that a branch is a small mixture, not a single pure element.

How branches are used day to day

Combined with the ten stems, the branches make the sixty two-character names that label years and days - 壬子, 癸丑 and so on. The second character of a day name is its branch, and it tells you the element that is strong that day and the hours that share it.

Like the stems, the branches are a counting system first. The animals and seasons make them vivid, but what a reading actually uses is plain: which element, which season, which hours.

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Traditional theory · for lifestyle reference. Not medical, financial or personal advice.