Korea under Japanese rule

From 1910 to 1945, Korea was ruled by the Empire of Japan as a colony under the name Chōsen, the Japanese reading of "Joseon".
Japan first took Korea into its sphere of influence during the late 1800s. Both Korea and Japan had been under policies of isolationism, with Joseon being a tributary state of Qing China. However, in 1854, Japan was forcibly opened by the United States. It then rapidly modernized under the Meiji Restoration, while Joseon continued to resist foreign attempts to open it up. Japan eventually succeeded in forcefully opening Joseon with the unequal Japan–Korea Treaty of 1876.
Afterwards, Japan embarked on a decades-long process of defeating its local rivals, securing alliances with Western powers, and asserting its influence in Korea. Japan assassinated the defiant Korean queen and intervened in the Donghak Peasant Revolution. After Japan defeated China in the 1894–1895 First Sino–Japanese War, Joseon became nominally independent and declared the short-lived Korean Empire. Japan defeated Russia in the 1904–1905 Russo-Japanese War, making it the sole regional power.
Japan acted quickly to fully absorb Korea and to turn it into an integral part of its home territory. It first made Korea a protectorate under the Japan–Korea Treaty of 1905, and ruled the country indirectly through the Japanese resident-general of Korea. After forcing Emperor Gojong to abdicate in 1907, Japan formally colonized Korea with the Japan–Korea Treaty of 1910. For decades it administered the territory by its appointed governor-general of Chōsen, who was based in Keijō.
Japan made sweeping changes in Korea. Under the pretext of the racial theory known as Nissen dōsoron, it began a process of Japanization, eventually functionally banning the use of Korean names and the Korean language altogether. Its forces transported tens of thousands of cultural artifacts to Japan. Hundreds of historic buildings, such as the Gyeongbokgung and Deoksugung palaces, were either partially or completely demolished.
Japan built infrastructure and industry to develop the colony. It directed the construction of railways, ports, and roads, although in numerous cases, workers were subjected to extremely poor working circumstances and discriminatory pay. While Korea's economy grew under Japan, scholars argue that many of the infrastructure projects were designed to extract resources from the peninsula, and not to benefit its people. In addition, Koreans faced heavy taxation, with rates in some cases exceeding 50%. Most of Korea's infrastructure built during this time was destroyed during the 1950–1953 Korean War.
These conditions led to the birth of the Korean independence movement, which acted both politically and militantly, sometimes within the Japanese Empire, but mostly from outside of it. Koreans were subjected to a number of mass murders, including the Gando Massacre, Kantō Massacre, Jeamni massacre, and Shinano River incident.
Beginning in 1939 and during World War II, Japan mobilized around 5.4 million Koreans to support its war effort. Many were moved forcefully from their homes, and set to work in generally extremely poor working conditions. Many women and girls were forced into sexual slavery as "comfort women" to Japanese soldiers.
After the surrender of Japan at the end of the war, Korea was liberated from Japanese colonial rule, but was immediately divided into occupation zones under the rule of the Soviet Union and of the United States.
The legacy of Japanese colonization has been hotly contested, and it continues to be extremely controversial. There is a significant range of opinions in both South Korea and Japan, and historical topics regularly cause diplomatic issues. Within South Korea, a particular focus is the role of the numerous ethnic Korean collaborators with Japan. They have been variously punished or left alone. This controversy is exemplified in the legacy of Park Chung Hee, South Korea's most influential and controversial president. He collaborated with the Japanese military and continued to praise it even after the colonial period.
Until 1964, South Korea and Japan had no functional diplomatic relations, until they signed the Treaty on Basic Relations. It declared "already null and void" all treaties made between the Empires of Japan and Korea on or before 22 August 1910. Despite this, relations between Japan and South Korea have oscillated between warmer and cooler periods, often due to conflicts over the historiography of this era.

Terminology

During the period of Japanese colonial rule, Korea was officially known as Chōsen, although the former name continued to be used internationally.
In South Korea, the period is usually described as the "Imperial Japanese compulsive occupation period". Other terms, although often considered obsolete, include "Japanese Imperial Period", "The dark Japanese Imperial Period", and "Wae administration period".
In Japan, the term "Chōsen of the Japanese-Governed Period" has been used.

Background

Political turmoil in Korea

Japan–Korea Treaty of 1876

On 27 February 1876, the Japan–Korea Treaty of 1876 was signed. It was designed to open up Korea to Japanese trade, and the rights granted to Japan under the treaty were similar to those granted Western powers in Japan following the visit of Commodore Perry in 1854. The treaty ended Korea's status as a protectorate of China, forced opening of three Korean ports to Japanese trade, granted extraterritorial rights to Japanese citizens, and was an unequal treaty signed under duress of the Ganghwa Island incident of 1875.

Imo Incident

The regent Daewongun, who remained opposed to any concessions to Japan or the West, helped organize the Mutiny of 1882, an anti-Japanese outbreak against Queen Min and her allies. Motivated by resentment of the preferential treatment given to newly trained troops, the Daewongun's forces, or "old military", killed a Japanese training cadre, and attacked the Japanese legation. Japanese diplomats, policemen, students, and some Min clan members were also killed during the incident. The Daewongun was briefly restored to power, only to be forcibly taken to China by Chinese troops dispatched to Seoul to prevent further disorder.
In August 1882, the Japan–Korea Treaty of 1882 indemnified the families of the Japanese victims, paid reparations to the Japanese government in the amount of 500,000 yen, and allowed a company of Japanese guards to be stationed at the Japanese legation in Seoul.

Kapsin Coup

The struggle between the Heungseon Daewongun's followers and those of Queen Min was further complicated by competition from a Korean independence faction known as the Progressive Party, as well as the Conservative faction. While the former sought Japan's support, the latter sought China's support.
On 4 December 1884, the Progressive Party, assisted by the Japanese, attempted the Kapsin Coup, in which they attempted to maintain Gojong but replace the government with a pro-Japanese one. They also wished to liberate Korea from Chinese suzerainty. However, this proved short-lived, as conservative Korean officials requested the help of Chinese forces stationed in Korea. The coup was put down by Chinese troops, and a Korean mob killed both Japanese officers and Japanese residents in retaliation. Some leaders of the Progressive Party, including Kim Okkyun, fled to Japan, while others were executed. For the next 10 years, Japanese expansion into the Korean economy was approximated only by the efforts of tsarist Russia, but eventually would be annexed by Japan in 1910.

Donghak Revolution and First Sino-Japanese War

The outbreak of the Donghak Peasant Revolution in 1894 provided a seminal pretext for direct military intervention by Japan in the affairs of Korea. In April 1894, Joseon asked for Chinese assistance in ending the revolt. In response, Japanese leaders, citing a violation of the Convention of Tientsin as a pretext, decided upon military intervention to challenge China. On 3 May 1894, 1,500 Qing forces appeared in Incheon. On 23 July 1894, Japan attacked Seoul in defiance of the Korean government's demand for withdrawal, and then occupied it and started the Sino-Japanese War. Japan won the First Sino-Japanese War, and China signed the Treaty of Shimonoseki in 1895. Among its many stipulations, the treaty recognized "the full and complete independence and autonomy of Korea", thus ending Joseon's tributary relationship with Qing, leading to the proclamation of the full independence of Joseon in 1895. At the same time, Japan suppressed the peasant revolt with Korean government forces.

Assassination of Queen Min

The Japanese minister to Korea, Miura Gorō, orchestrated a plot against 43-year-old Queen Min, and on 8 October 1895, she was assassinated by Japanese agents. The Korean military unit, Hullyŏndae, participated in the assassination. With Korean aid, Japanese assassins were allowed to enter the palace Gyeongbokgung. In 2001, Russian reports on the assassination were found in the archives of the Foreign Ministry of the Russian Federation. The documents included the testimony of King Gojong, several witnesses of the assassination, and Karl Ivanovich Weber's report to Aleksey Lobanov-Rostovsky, the Foreign Minister of Russia, by Park Jonghyo. Weber was the chargé d'affaires at the Russian legation in Seoul at that time. According to a Russian eyewitness, Seredin-Sabatin, an employee of the king, a group of Japanese agents entered Gyeongbokgung, killed Queen Min, and desecrated her body in the north wing of the palace.
The Heungseon Daewongun returned to the royal palace the same day. On 11 February 1896, Gojong and the crown prince fled for protection at the Russian legation in Seoul, from which he governed for about a year.

Democracy protests and the proclamation of the Korean Empire

In 1896, various Korean activists formed the Independence Club. They advocated a number of societal reforms, including democracy and a constitutional monarchy, and pushed for closer ties to Western countries in order to counterbalance Japanese influence. It went on to be influential in Korean politics for the short time that it operated, to the chagrin of Gojong. Gojong eventually forcefully disbanded the organization in 1898.
In October 1897, Gojong returned to the palace Deoksugung, and proclaimed the founding of the Korean Empire at the royal altar Hwangudan. This symbolicly asserted Korea's independence from China, especially as Gojong demolished a reception hall that was once used to entertain Chinese ambassadors in order to build the altar.