After Emperor Wu of the Han Dynasty, Jiazi era began, and 60 years old was Jiazi. The last Jiazi year is 1984, and the next Jiazi year is 2044.
The extended data lunar calendar is a chronological system, and the "year" in Jiazi year is from the first day of the first month of that year to New Year's Eve. This is the calendar rule of the Lunar New Year, which is uncontroversial.
However, the lunar calendar only borrows the date of official support, which cannot change the principle that the date of official support is counted from beginning of spring. Because the official calendar and the lunar calendar are two different calendars. The two are different in the starting point of a year, the division rules of months and the number of days in a year.
Now most historians agree that the Yellow Emperor was located in 2697 BC, so the first year of Jiazilun was 2697 BC.
The second Jiazi wheel is from 2637 BC to 2578 BC, so the second Jiazi year is 2637 BC.