September 12 is the 255th day of the Gregorian calendar (256th in leap years).
490 BC - Battle of Marathon
372 - The filial piety system of Dongjin succeeds the father-in-law to the throne.
1921 - Japanese Occupation: Independence activist Kim Ik-sang belonging to the Uiyeol gang threw a bomb at the Governor-General of Korea to assassinate Governor Saito
The U.S. Military Government and the Governor-General of Korea dissolved the Central Committee, and each member of the Central Committee under the Acting Chairperson and Vice-Chairman Park Jung-yang was dismissed.
Chi-ho Yun resigns from his position as a member of the Japanese aristocrat.
1950 - Korean War: The Battle of Yeongcheon ends.
1952 - The Korean War: The People's Republic of China and the Soviet Union issue a joint declaration on the Korean War Armistice Talks
1961 - The Korea Newspaper Ethics Committee, an autonomous deliberation body for journalists in Korea, was established.
1969 - Vietnam War: US forces resume bombing of North Vietnam by order of President Richard Nixon
1974 - Emperor Haile Selassie I of Ethiopia, deposed by the military
1980 - Coup d'état in Turkey led by Chairman of the Joint Chiefs of Staff Kenan Evren.
1982 - People's Republic of China abolished the party president system, and Hu Yaobang was elected general secretary of the party.
1983 - The Republic of Korea sends a letter to the USSR Embassy in the US asking for compensation for the loss of the KAL plane.
1997 - US President Bill Clinton appoints Stephen Bosworth, secretary-general of the Korean Peninsula Energy Development Organization (KEDO), as US ambassador to Korea
The Republic of Korea's Suspicious Photographic Identification Commission announced that the 1974 Inhyuk Party Reconstruction Committee case was a manipulation by the Central Intelligence Agency.
The United Nations Command in Korea and the Democratic People's Republic of Korea and the Democratic People's Republic of Korea sign an agreement to transfer management rights related to the construction of the Demilitarized Zone (DMZ).
2003 - Typhoon Maemi hits the southern part of the Korean Peninsula, killing 127 people and causing property damage of 4.22 trillion won.
2005 - The Liberal Democratic Party of Japan, led by Junichiro Koizumi, wins the general election in Japan.
Japanese Prime Minister Shinzo Abe resigns.
A Philippine court finds former president Joseph Estrada guilty of financial misconduct during his tenure and sentences him to life in prison.
2009 - A 73-year-old woman in South Korea died from swine flu, the fifth death in the country.
Two people were killed and 19 others were injured in a 9-car crash near the Uijeongbu Interchange on the Seoul Outer Ring Expressway.
Massive flooding in Colorado, US, kills 4 people.
2014 - Idol singer Seungri, a member of Big Bang, gets involved in a drunk driving controversy.
2016 - A magnitude 5.8 earthquake occurred 8 km south-southwest of Gyeongju-si, Gyeongsangbuk-do, injuring 23 people.
The Korea Centers for Disease Control and Prevention was promoted to the Korea Centers for Disease Control and Prevention.
Kyoto Protocol Greenhouse Gas Reduction Target Deadline
1609 – Henry Hudson, an English explorer, discovers the Hudson River near New York, USA.
1959 - The Soviet Union launches the Luna 2 space probe. Luna 2 will be the first spacecraft to reach the moon.
1988 - The 94th International Olympic Committee (IOC) General Assembly opens in Seoul. (~16 days)
1991 - The 2nd Korean National Sports Festival opened with 1,652 compatriots from 88 countries participating
1999 - Serena Williams wins her first US Open tennis win as a black woman in 41 years
2001 - Seoul Woneum Broadcasting was launched in Seoul, Korea.
2005 - Hong Kong Disneyland opens.
2011 - Miss Universe 2011 was held in Sao Paulo, Brazil.
2012 - Hana Financial Group of Korea established the Hana Foreign Exchange Women's Professional Basketball Team.
2013 - In 2013 Professional Baseball, the Doosan Bears succeeded in avenging the 508 Battle by winning a 7-point comeback victory against the SK Wyverns.
2020 - Suwon-Handae-mae section of the Suin Line of the Seoul Metropolitan Subway will be opened and directly connected to the Suin/Bundang Line
2021 - Korea