How to calculate China around A.D.?

AD, that is, Gregorian calendar chronology, is a method of chronology that originated from western society. The Gregorian calendar starts from the year when Jesus was born, which is called BC before Jesus was born. 1949 On September 27th, the first plenary session of China People's Political Consultative Conference passed that the newly established People's Republic of China (PRC) adopted the Gregorian calendar and the Gregorian calendar year commonly used by most countries in the international community. The so-called year 2020 is the year from the first year of AD. However, many people may not know, what year was the first year of China? How is it calculated after BC and AD?

The first year of AD is the first year of the Gregorian calendar, counting from the legendary year when Jesus Christ was born. In China, this year happened to be the first year of the reign of Emperor Ping of the Western Han Dynasty. BC 1 BC 10 year 10 month, BC 17 year, Liu _ was Emperor Han Ping, and the following year (A.D. 1 year) was the first year of Yuan Dynasty. Taking this year as the boundary, the time before this is called BC, and the time after this is called N years after AD, or N years for short.

It should be noted that although 0 is a natural number, it did not exist in 0 BC or 0 AD. The year after BC 1 year is AD 1 year, which is the first year of AD. Although the chronology of BC is reversed, the figures in the back are smaller than those in the front. For example, in 202 BC, it was established in the Western Han Dynasty, which was later than 22 1 BC, and was established in the Qin Dynasty. However, the specific month of each year is still being counted, with 1 in front and 12 behind, and the date is the same, with the first day in front and the first day behind.