The traditional Korean method of counting ages deems children one year old from the moment they are born and adds another year each New Year’s Day or Jan. 1 — instead of the day they are born like in the West.

For purposes such as military conscription or the legal drinking age – otherwise known as the Calendar age – Koreans use the same method but deem the child zero at birth. Meanwhile, the South Korean medical system adopted the international mode of calculating age in the 1960s, counting from zero at birth and adding a year on every birthday.

In action, this means that a child born on Dec. 31 in the U.S. and South Korea will be two years apart in age by Jan. 1. It also means that to their parents, their army officer, and their doctor, they may have three different ages.

But starting in June 2023, the traditional method of counting age will be officially scrapped across all “judicial and administrative areas,” and new laws will come into place stipulating that only the international method of counting ages will be used.

“The state and local governments shall encourage citizens to use their ‘international age’ and conduct necessary promotion for that,” the bill says on the parliament website.

“The revision is aimed at reducing unnecessary socio-economic costs because legal and social disputes, as well as confusion, persist due to the different ways of calculating age,” Yoo Sang-bum of the ruling People Power party told parliament.

Who wouldn’t want to be a year or two younger?

The system is a remnant of the Chinese way of calculating age centered around the Lunar new year. In pre-modern times, Chinese societies calculated age by adding one year at birth and then a year for how many Lunar years have passed. There is a theory that the concept began at a time when there were no regular calendars, so people would often ignore the day of their birth and simply add a whole year on the first day of the lunar calendar of the Spring festival.

In the context of a child’s horoscope, this method is still considered relevant throughout life in many Chinese societies around the world.

But while China has largely stopped using this method of calculating ages on legal documents, the tradition has stayed alive in Korea and Taiwan. (Japan also calculated age this way until 1902, when a law was passed to convert to the modern age system.)

Korea adopted Jan. 1 as the day an additional year was added, as the country began observing the Gregorian calendar in 1869.  

According to Korean lawmakers, transitioning to the internationally accepted way of calculating age does more than just get rid of the confusion. The three different methods of calculating age also caused conflict by “fostering a culture of hierarchy based on age and avoiding certain months for childbirth,” lawmaker Hwang Ju-hong wrote in another bill introduced in 2019, CNN reported.