Perhaps you were familiar with fan death, but were you aware of another bit of South Korean quirkiness, the concept of “Korean age”?

Under this system, which has its roots in China, babies are considered a year old on the day they’re born, with a year added every January 1.

In some circumstances, South Koreans also use their “calendar age” – a mash-up of international age and Korean age – which consider babies as zero years old on the day they’re born and adds a year to their age every January 1.

While it doesn’t match most of the rest of the world, a one-based counting system for age isn’t nonsensical. Adding a year on January 1, however, seems preposterous.

Take “Gangnam Style” singer Psy, for example. Born on December 31, 1977, he is considered 45 by international age; 46 by calendar year age; and 47 by Korean age.

I’m delighted that one of the most famous Koreans in the world, Psy, has the birthday which best exemplifies how ludicrous these old systems were. Under the previous systems, at most 24 hours after he was born, Psy was 1 or even 2 years old.