South Korea has developed into one of Asia’s most affluent countries since partition in 1948. The Communist North has slipped into totalitarianism and poverty.
The republic was proclaimed in 1948 and received UN-backed support from the US after it was invaded by the North two years later.
The Korean War ended in 1953 without a peace agreement, leaving South Korea technically at war for more than fifty years.
The following four decades were marked by authoritarian rule, during which government-sponsored schemes encouraged the growth of family-owned industrial conglomerates, including the Hyundai and Samsung groups.
They helped transform South Korea into one of the world’s major economies and a leading exporter of cars and electronic goods.
The US has tens of thousands of soldiers in the country.
President: Park Geun-hye
South Korea elected its first female president, Park Geun-hye, in a close-run contest in December 2012.
Her father President Park Chung-hee, ruled the country for 18 years after seizing power in a coup.
In 1974, at the age of 22, Ms Park became South Korea’s first lady when her mother was shot dead by a North Korean assassin’s bullet intended for her husband.
In September 2012 Ms Park issued a public apology for human rights abuses committed under her father.
South Korea is at the leading edge of the digital revolution. It is a trailblazer for high-speed and wireless internet.
Around 45 million South Koreans – out of a population of almost 49 million – were online by 2014 (InternetWorldStats).
South Korean TV soaps are popular across the region, including in China. They are part of the “Korean Wave” – the export of South Korean popular culture across Asia.
Some key dates in South Korea’s history:
1945 – After Second World War, Japanese occupation ends with Soviet troops occupying area north of the 38th parallel, and US troops in the south.
1948 – Republic of Korea proclaimed.
1950 – South declares independence, sparking North Korean invasion.
1953 – Armistice ends Korean War, which has cost two million lives.
1950s – South sustained by crucial US military, economic and political support.
1960s – Major programme of industrial development.
1988 – First free parliamentary elections.
2002 – Battle between South Korean and North Korean naval vessels along their disputed sea border is only one flare-up in the ongoing tension between the two states.
All copyrights for this article are reserved to bbc asia