Is it April 4th in Tomb-Sweeping Day every year?

Tomb-Sweeping Day is not only one of the twenty-four solar terms in China, but also an important sacrificial festival. The origin of Tomb-Sweeping Day can be traced back to the Zhou Dynasty. Astronomers in that dynasty studied the twenty-four solar terms, which were born by measuring the shadow of the sun with the method of soil return, so Tomb-Sweeping Day came into being. Is it April 4th in Tomb-Sweeping Day every year?

Speaking of Tomb-Sweeping Day, people will say that April and May are clear, but the actual time in Tomb-Sweeping Day is not necessarily April 5th, which means that the time in Tomb-Sweeping Day is not fixed. The main reason is related to Tomb-Sweeping Day's calculation method, which is not only based on the lunar calendar or the new history. Tomb-Sweeping Day was a solar term from the beginning, and now the 24 solar terms are divided according to the position of the sun on the ecliptic-the longitude of the sun.

But most ordinary people don't know the ecliptic. What is this? To talk about the yellow meridian of the sun, we must first talk about the 360 degrees of the yellow meridian. In fact, this is the degree of the earth's revolution. 360 degrees is divided into 24 equal parts, and each equal part is 15 degrees. This is a solar term, which adds up to 24 solar terms. However, the current Gregorian calendar adopts another method when dividing the share of the solar calendar, so the solar calendar is divided into the same 365, so there are 365 days. This is easy to explain, because the proportion of 24 equal parts and 365 equal parts is different, so from the Gregorian calendar, the date of solar terms will be different, that is, sometimes there will be a day difference. Because of this, the specific date of Tomb-Sweeping Day is not fixed on a certain day every year, which may be April 5 or April 4.

Traditional festivals such as Spring Festival, Lantern Festival and Mid-Autumn Festival are calculated according to the lunar calendar. The so-called lunar calendar means watching the moon go round and round, and when the sun shines directly at the equator, it is also the vernal equinox. At the vernal equinox, the sun's longitude is zero. When it is sunny, it is the longitude of the sun 15 degrees. This calculation method has a long history. It has been used for more than 300 years since 1645. You can also look at the night sky in an ancient way. If the bucket handle of the Big Dipper points to the southeast, it means that bucket handle points to Z, which means Tomb-Sweeping Day.

Tomb-Sweeping Day, also known as March Festival, is a traditional festival for ancestor worship and one of the legal holidays in China. Tomb-Sweeping Day holidays have existed since ancient times, and the holiday time of each dynasty is different. Tomb-Sweeping Day began in the Tang Dynasty. In the Xuanzong era, cold food and Qingming had a holiday together. 1935, the government of the Republic of China clearly stipulated that April 5th of each year was a national holiday in Tomb-Sweeping Day, and the time when Tomb-Sweeping Day became a national holiday in China was in 2008.

The time in Tomb-Sweeping Day may be different every year, and Tomb-Sweeping Day may be from April 4th to April 6th in the new calendar. In 2022, Tomb-Sweeping Day falls on the fifth day of the fourth lunar month, that is, the fifth day of the third lunar month, and Qingming is the fifth solar term. As a festival, Tomb-Sweeping Day is different from pure solar terms. Solar terms indicate phenological changes and seasonal order, while festivals contain customs, rituals and spiritual beliefs. Ancestor belief and sacrificial culture are important factors in the formation of Tomb-Sweeping Day, and the important carrier of Tomb-Sweeping Day is the inheritance of belief and family ethics.