China runs two calendars at once, with two more cycles layered over the second. That is not a curiosity — it is why a festival moves every year, why someone has two birthdays, and why 今天几号 and 今天初几 are different questions.
Without a plan: All four calendar pages
Four systems, used together
| System | Chinese | What it governs |
|---|---|---|
| The Gregorian calendar | 公历 gōnglì | Official and practical life — contracts, timetables, tickets, National Day |
| The traditional calendar | 农历 nónglì | Festivals, family birthdays, the dates nobody schedules a meeting by |
| The zodiac and stem-branch cycle | 生肖 · 干支 | Years, and a sixty-year cycle older than either calendar |
| The 24 solar terms | 节气 jiéqì | The agricultural year — when to plant, when the insects wake, what to eat |
Why a festival moves every year
Because festivals are set on the traditional calendar and you are reading them on the Gregorian one. The traditional calendar is lunisolar — months follow the moon, years are kept in step with the sun by inserting a thirteenth month when the drift gets too large.
So Spring Festival is always the same traditional date and never the same Gregorian one. Nothing is moving: you are converting between two systems, one of which has months of 29 or 30 days.
The zodiac is a cycle, not a horoscope
The twelve animals name years, and they sit inside a larger sixty-year cycle built from ten heavenly stems and twelve earthly branches. Sixty is the point where the two cycles realign, which is why a sixtieth birthday is the one that matters.
It is reference knowledge rather than belief. A year named by its animal appears in historical dates, in small talk about someone’s age, and in the superstition about your own zodiac year being the unlucky one — all of which come up in conversation long before you can discuss anything abstract.
The 24 solar terms
Twenty-four points dividing the solar year, each about a fortnight apart, each named for what the weather or the farm is doing: the insects waking to thunder, the grain rains, the great heat, the frost descending.
These are the oldest-feeling and most useful piece of vocabulary on the page, because they are still used. A weather report, a food article, a greeting on the right day — the terms are current language, not museum language, and they are the part of the calendar system a learner can deploy immediately.
What each page holds
A page per system, each with the same four sections: how it works, where it came from, how it is used in China today, and why it matters if you are learning the language. Plus the short titled facts that are the bits people actually repeat — that the rat cheated to win, that the cat was left out, that China switched to the Gregorian calendar in 1912.
Every page also shows today’s date in that system, which is the fastest way to understand what the system is: seeing the same day written four ways does more than a paragraph explaining it.
Common questions
The Gregorian one, for anything you schedule or buy. The traditional one, to know when a festival is and why your friend’s birthday is on a different day at home than at work.