What is a perpetual calendar in popular terms?

Simply put, a perpetual calendar is an almanac that can be queried for many years.

Interpretation of Ci Hai: Including almanac of several years or applicable to several years.

Then why not call it a multi-year calendar? Where did it come from? Initially, it named the calendar "perpetual calendar" to commemorate the 10,000-year achievement of the first calendar editor. This title is used to address all kinds of calendars.

Nowadays, the perpetual calendar is not simple, it is all-encompassing, and it can have zodiac signs, constellations and so on.

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