Is the lunar calendar a new calendar or an old calendar?

Lunar calendar, also known as summer calendar, lunar calendar and old calendar, is one of the traditional calendars in East Asia. The lunar calendar belongs to a kind of lunar calendar, and an average calendar month is equal to a new moon. However, the leap month is set to make the average calendar year a tropic year, and the 24 solar terms are set to reflect the changing characteristics of the seasons (the annual movement of the direct point of the sun), so there is also a solar calendar. Today, almost all Chinese in the world, as well as countries such as North Korea, South Korea, Vietnam and early Japan still use the lunar calendar to calculate traditional festivals such as Spring Festival, Mid-Autumn Festival and Dragon Boat Festival. Because this calendar is said to have originated in the Xia Dynasty, it is called the Xia calendar.