Republic of Korea (South Korea)
Who & why: the Republic of Korea is proclaimed on 15 August 1948 in the American-occupied south, with Syngman Rhee as its first president, formalizing the division that followed Japan's 1945 defeat. North Korean forces invade the south in June 1950, starting the Korean War; UN and mainly American forces intervene, Chinese forces enter on the North's side, and the 1953 armistice (never replaced by a formal peace treaty) leaves the peninsula divided along a heavily fortified line near the original 38th parallel. South Korea moves from decades of authoritarian rule under successive military-linked presidents to full multi-party democracy by the late 1980s, and grows into one of the world's largest economies.
What it represents: the Taegukgi, officially promulgated on 27 January 1883 and adopted by the Constituent National Assembly on 12 July 1948; Wikipedia says the current geometry was standardised on 15 October 1949, exact dimensions and etiquette were codified on 21 February 1984, and a presidential decree fixed the colours in 1997 (25 October per FOTW), with a National Flag Law in July 2007. A white field for peace and purity, a red and blue taegeuk for yin and yang, and four trigrams.
Wikipedia: 12 July 1948 adopted; 15 October 1949 geometry standardised; 21 February 1984 dimensions codified; 1997 decree fixed colours. FOTW: 25 October 1997 presidential ordinance on standard specification; July 2007 National Flag Law.
- Flag of South Korea — Wikipedia compiled
- South Korea — Flags of the World (CRW Flags) compiled
Not established: FOTW is silent before 1997; the 1883 and 1948 dates rest on Wikipedia.