Chinese New Year
In the past, the Chinese emperors did not number their years from one place. Instead, they gave names to eras (groups of years) any time they wanted. Since they still changed its number at every new year festival, the first year of a new era might only be a few days long. One example of this is the "1st year of Kaiyuan" during the Tang, which lasted a week or so in 713 AD. In the same way, people in China and around East Asia did not count their ages from zero or add one year at every birthday. They counted birth as the start of their 1st year and added another year upon the 7th day of the New Year, which they called People's Day (Rénrì). This came from an old story about how a goddess named Nüwa made all the animals. The day she made people was used as the common birthday for everyone. In this way, people sometimes called a baby who born on the 6th day of the New Year a 2-year-old only a few hours after its birth. (Today, it is much more common in China to count age starting at zero and add years at birthdays, like in English-speaking countries.)