Why the traditional Chinese practice of nominal age makes people up to 2 years older

Age calculation in China is probably one of the most confusing aspects of Chinese culture, even for Chinese people themselves, because two systems are used. One system is the international standard: a person’s age is calculated from their date of birth. The other, the traditional nominal-age system, or xu sui, adds a year at the start of each lunisolar year. Under the xu sui system, a person’s nominal age can be up to two years greater than their actual age. The system is more commonly used in...