For three years all citizens of South Korea have become by law one or two years younger. But why ever?
The question, in truth, should be put in other terms: until June 28, 2023, Koreans were one or two years older than their peers in the rest of the world. This is because, until a few years ago, in South Korea they did not use chronological age as in the rest of the world – that is, it is counted starting from 0 and increasing the years by 1 at each birthday – but rather a different way of counting age, which we could call “traditional”.
The traditional Korean age was calculated like this by law: when you are born, you are already 1 year old and your birthday is not on the day of your birth, but every January 1st. This means, for example, that a person born on 10 June 2020, today (in February 2026) would not be 5 years old, but rather 7, because they were born 1 year old and already had their birthday in January, instead of having their birthday in June.
The most paradoxical case was that of those born on December 31st: on one day of life they were 1 year old, and on the second day of life – January 1st – they were already 2 years old!
However, before 2023, this was not the only way of counting age in South Korea. There was in fact a separate system to calculate the age at which one starts going to school, can enter military service or can drink alcohol. In this case the age was counted starting from 0, but everyone’s birthday was still January 1st.
Then there was also the international age, which from June 2023 became the official one, that is, the chronological age that we use.
And that’s why since 2023, by adopting the international age, South Koreans have magically seen their age drop by a year or two. The choice to adopt the chronological age was dictated by the need not to create more chaos in case of trips abroad or in general bureaucratically.
But why was this strange way of counting age used until then? There are two possible reasons: one is that when expressing the age of an individual, we also wanted to take pregnancy into account, a bit as if we started counting at the moment of conception; the other, however, could derive from the fact that in Asian culture, the concept of 0 was not initially present.
