What is Eto? The Japanese zodiac explained
Eto (干支) is the Japanese name for the sexagenary cycle, in which ten heavenly stems combine with twelve earthly branches to count years, months and days. In everyday Japanese, eto often just means your zodiac animal.
Ten stems and twelve branches
The ten stems (jikkan) are Wood, Fire, Earth, Metal and Water, each in a yang and a yin form. The twelve branches (jūnishi) are the twelve zodiac animals, from the Rat to the Pig.
Pairing them in order gives sixty combinations, from Kinoe-ne (甲子, Yang Wood Rat) to Mizunoto-i (癸亥, Yin Water Pig). After sixty years the cycle returns, which is why the 60th birthday, kanreki, is celebrated in Japan as a rebirth.
Not just years
In Japan the same cycle is still printed in calendars for every day. Some days are traditionally lucky: Tiger days for travel and buying a wallet, Snake days for wealth, and Kinoe-ne days for Daikoku, a god of good fortune.
Four Pillars of Destiny (BaZi; shichū suimei in Japanese) reads a person from the stems and branches of their birth year, month, day and hour. The stem of the birth day, the Day Master, represents you.
When does the year change?
This site uses the solar calendar, where the year begins at Risshun, the start of spring, around 4 February. This is how traditional Japanese almanacs and Four Pillars practitioners count it.
In China and Korea, the animal is popularly counted from Lunar New Year, which falls between 21 January and 20 February. If you were born between January and mid-February, check both.
Eto in Japanese life
New Year cards (nengajō) feature the coming year's animal, and people whose animal matches the new year (toshi-otoko and toshi-onna) are traditionally chosen to throw the beans at Setsubun, as they are thought to bring good luck. The animals also mark the twelve directions and the twelve two-hour periods of the old clock.