The ten Heavenly Stems (天干)

The ten Heavenly Stems are the first of the two sets of signs used to count years, months, days and hours in the East Asian calendar. Each stem is one of the five elements in either its yang or its yin form, and each has a traditional picture that makes it easy to remember.

Ten stems, five elements, two polarities

The stems come in pairs. The first two are Wood, the next two Fire, then Earth, Metal and Water. Within each pair the first stem is yang - the outward, larger, more forceful form - and the second is yin, the inward, smaller, more yielding form. So there are five elements times two polarities: ten stems.

The order is not arbitrary. It follows the generating cycle, in which Wood feeds Fire, Fire makes Earth, Earth bears Metal, Metal carries Water and Water grows Wood. Reading the stems from first to last is reading one turn of that cycle.

The ten stems one by one

甲 Jia. Jia is Yang Wood, pictured as a tall tree or a timber beam. The image is upright growth: a trunk that goes straight up and does not bend easily. In chart reading it is used as shorthand for a direct, steady, principled quality, and it is the stem that opens the cycle of ten.

乙 Yi. Yi is Yin Wood: grass, vines and garden flowers. Where Jia grows straight, Yi grows around things. The image is flexibility - a plant that finds the light by bending. It is the gentle, adaptable side of Wood.

丙 Bing. Bing is Yang Fire, the sun. It gives light to everything at once and cannot be hidden, so it stands for warmth that is open and generous. Bing is the Fire you see from far away.

丁 Ding. Ding is Yin Fire: a candle, a lamp, a hearth. It is small, close and focused, the light you read by. It stands for attention and quiet warmth rather than blaze.

戊 Wu. Wu is Yang Earth, a mountain or a city wall. The image is mass and stillness: something that holds its place and that other things can lean on. It is the dependable, slow-to-move side of Earth.

己 Ji. Ji is Yin Earth: the soil of a field or a garden. It is soft, moist and productive, the earth that things actually grow in. It stands for care, nourishment and patient cultivation.

庚 Geng. Geng is Yang Metal, pictured as an axe, a sword or unworked ore. It is hard and decisive: the stem of cutting, of clear lines and of things settled. It is Metal before it has been polished.

辛 Xin. Xin is Yin Metal: jewellery, a needle, refined gold or silver. It is small, precise and bright. The image is refinement - Metal that has been worked until it shines.

壬 Ren. Ren is Yang Water, a great river or the sea. It moves, carries things along and is hard to hold back. It stands for breadth, flow and resourcefulness.

癸 Gui. Gui is Yin Water: rain, dew and mist. It falls quietly and soaks in, reaching places a river cannot. This is why 癸水 is so often glossed simply as "rain" or "dew" - the soft, nourishing, patient side of Water. Gui closes the cycle of ten.

Where you meet the stems

A Four Pillars chart has four columns - year, month, day and hour - and each column has one stem on top and one Earthly Branch below. That gives four stems in a chart. The stem of the day column is called the Day Master and is read as the person themselves; the other three stems are read in relation to it.

The same ten stems also name days in an ordinary almanac. Combined with the twelve branches they form a cycle of sixty, so every day has a two-character name such as 壬子. When an app says "today is a Water day", it is reading the stem of that name.

The images are teaching aids, not predictions. Calling 癸 "rain" tells you which element and which polarity is meant; it does not say anything fixed about a person. Used that way the ten pictures are a compact, memorable alphabet for the five elements.

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