When giving their age to foreigners, South Koreans typically say two numbers. Their "international age," or the number of years since they were born, and their "Korean age," which could be one -- or even two -- years higher.

In Korea, babies are considered a year old on the day they're born, meaning that someone born in January 1990 is 30 in Korea, not 29. For those born late in the year, the gap can be even greater. A baby born on December 31 turns two on January 1.

This can cause a great deal of confusion, which lawmaker Hwang Ju-hong is determined to change.

South Korea is the "only nation" in East Asia to still use the traditional system, Hwang said when he introduced a bill into parliament earlier this year to bring it in line with the international norm.

Confusing tradition

The Korean age system has its roots in China. The Chinese language and writing system were once in wide use in Korea, and influenced the development of modern Korean.

In Chinese, age is traditionally written in an ordinal system, beginning with one. The same is true in Korean. A baby is said to be in its first year, or han sal, at birth, and on December 31 it enters its second year, du sal. When expressed in English han sal becomes "one-year-old," creating confusion.

While in China the traditional system has fallen out of use, people still linguistically distinguish between someone's nominal age (xusui), based on the traditional system, and real age (shisui), even if most will give the latter -- which also counts legally -- when asked.

The fundamental difference is that this system begins the count at one, rather than zero. While this may seem confusing, we do this in English as well; think of the 2000s vs the 21st century -- in the first, we count 2000 years from 0AD, while the second regards 0-100AD as the first century, not century zero.

In Japan, a traditional system in which people's age went forward by a year on New Year's Day was abandoned at the start of the 20th century, though it remained in partial use until the 1950s when a law was passed to adopt the international system.

Laws in South Korea are currently a hodgepodge of different systems. People use the traditional Korean age in everyday life, but their legal age is for most purposes based on the international calculation. However for certain laws, including those on age limits for movies, the measure is based on the year someone is born, regardless of month. This means two people born in January and December 1990 are judged to be the same age.

"The difference in the age calculation methods used in legal and everyday life had various adverse effects such as: wasting unnecessary administrative costs, creating confusion in information exchange due to its difference with other countries and conflict due to fostering a culture of hierarchy based on age and avoiding certain months for childbirth," Hwang's bill argues.

If passed, his bill will mean South Korea makes the international system "mandatory in all legal affairs and official documentation." Local governments and societies will also be encouraged to adopt it for consistency.

While Hwang claims widespread support from other MPs, his bill may face delays that could sink it. South Korea's National Assembly is deadlocked over controversial election bills, meaning lawmakers are not considering other legislation.

If Hwang's bill is not debated and voted upon during the current session, it will be scrapped and he will have to reintroduce it after next year's elections.