Eto: the ten stems and the twelve branches

In short

Ten stems and twelve branches

The sixty-year cycle came to Japan from China long ago. It combines the ten stems (jikkan) and the twelve branches (juni-shi), and has been used to show long spans of years and days instead of numbers.

The ten stems are linked to the ideas of yin and yang and the five elements. For example, the first is called kinoe, “the elder brother of wood”, and the second kinoto, “the younger brother of wood”. Fire, earth, metal and water follow in the same way.

The twelve branches

In China, the twelve branches were used from long ago to name the months of the calendar, the hours of the day and the directions.

They were at first only symbols showing the order of the twelve months. Later they were linked to animals.

For directions, north is the first branch, ne, and the names go round toward the east. The line joining ne (north) and uma (south) is called shigo-sen, the meridian.

Years and a 60-year cycle

Using the cycle for years grew out of an old way of counting years by the position of Jupiter. By the time of the Later Han dynasty in China, the cycle was simply set out in order, not tied to Jupiter, and this way continues today.

Because the cycle goes round once in 60 years, turning 60 is called kanreki.

In Japan, people write the year’s branch on their New Year cards. The names of events from history lessons, such as the Jinshin War and the Boshin War, contain eto. By counting the cycle, you can tell when they happened within a span of 60 years.

Think about it

• Q1The twelve branches first showed the order of the months. Why might people later link them to animals?
• Q2Ne is north and uma is south. Find the word “meridian” on a map. What does it join?
• Q3Does your culture give names to years? How do they repeat?

There is no single right answer. Talking it over with someone at home is a good way to learn.