A South Korean law will make people a year or two younger. There were three ways Koreans could tell their age. One was an "international age". A baby is a year old a year after it is born. The second was a "Korean age" – a baby is one when they are born, and a year is added every January. There was also a "calendar age".

Age in Korea is now simpler. Documents will use the international age. This will be the age for drinking, getting married, and smoking. Some people will still use the Korean age. A woman was happy. She is two years younger. She tweeted: "I turned two years old two weeks after I was born, as I was born in December."