<Tr> <Th> Revised Romanization </Th> <Td> hanguk pyojunsi </Td> </Tr> <Tr> <Th> McCune--Reischauer </Th> <Td> han'guk p'yojunsi </Td> </Tr> <P> South Korea has one timezone, Korea Standard Time (UTC + 09: 00), which is abbreviated KST . South Korea does not currently observe daylight saving time, but experimented with it during the 1988 Summer Olympics in Seoul . North Korea used Korea Standard Time until 2015, when it adopted Pyongyang Standard Time (UTC + 08: 30). </P> <P> In 1434, inventor Jang Yeong - sil developed Korea's first automatic water clock, which King Sejong adapted as Korea's standard timekeeper . It is likely that Koreans used water clocks to keep time prior to this invention, but no concrete records of them exist . In 1437, Jang Yeong - sil, with Jeong Cho, created a bowl - shaped sundial called the angbu ilgu (Hangul: 앙부일구), which King Sejong had placed in public so anyone could use it . </P>

Are there different time zones in south korea