Are there different two-year lunar calendars and solar calendars that completely overlap in the perpetual calendar? How many years are they repeated? What are the rules and how to calculate them?

Every day of the year is impossible, but one day is possible;

Every 19 years, the Gregorian calendar falls on the same day.

This situation is mainly the result of the leap of the lunar calendar. 19 Why is there a coincidence? The number of days in each month in the lunar calendar is determined according to the cycle of the moon. In fact, the average number of days per month is 29.5306. If multiplied by 12, there are only 354.3672 days in a year. One revolution of the earth around the sun (tropical year and solar year) is 365.2422 days, so the lunar year 1 the actual number of days is less than that of the sun 10.875 days, almost 1 1 day, 19 is 209 days less.

209 days divided by 30 is 6.9666, that is to say, 19 years, the lunar calendar is almost 7 months shorter than the solar calendar. In order to make the difference between the lunar calendar and the solar calendar not too much, it is necessary to make up these seven months.

China's lunar calendar is actually a typical lunar calendar, which is formulated in consideration of the movement cycle of the moon around the earth and the movement cycle of the earth around the sun. In order to make up for these seven months, people adopt the method of setting leap months in the lunar calendar-seven leap months in nineteen years, that is, nineteen years of the lunar calendar, and 12 is a normal year, every 65438. Plus seven leap years (3, 5, 8, 1 1, 14, 17, 19), every 1 leap year has 13 months.

In this way, the number of days in the 19 solar year is almost equal to the number of days in the 19 lunar year. Therefore, whenever the birthday is 19 or 19 multiplied by the age, there is a chance that the solar calendar birthday and the lunar calendar birthday are on the same day.

I don't know if I remember 200 1, the National Day of the Gregorian calendar 10 and the Mid-Autumn Festival on the 15th day of the eighth lunar month are the same day. Further, the National Day and Mid-Autumn Festival of 19 and 1982 also coincide; Further on, the Mid-Autumn Festival of 19 and 1963 is 10, and the difference is only 1 day-whether it is a lunar month or a solar year, their exact days are not integers but decimals, and the days of lunar calendar and solar calendar 19 are still slightly different. Decades or even hundreds of years later,