|This article needs additional citations for verification. (July 2014)|
|Spouse||Lady Gim Sudeok, Princess Duk-in
Lady Sugwan, concubine
Lady Suin, concubine
Cho Byungsuk, concubine
Lady Sugyung, concubine
Hong Jeongsun, concubine
Kim Hyesu, concubine
Lady Sudeok, concubine
Lady Sugwan, concubine
Lady Sugil, concubine
Gim Geumdeok, concubine
|Issue||Yi Geon, Kenichi Momoyama
Wu, Prince of Korea
Seok, Prince of Korea
|Father||Emperor Gojong of Korea|
|Mother||Lady Yang, concubine|
|Born||30 March 1877|
|Died||15 August 1955
Seongrak Manor, Seongbuk-dong, Seongbuk-gu, Seoul, South Korea
|Revised Romanization||Uichinwang I Gang or Uihwagun|
|McCune–Reischauer||Ŭich'inwang I Kang or Ŭihwagun|
Yi Kang, the Prince Imperial Uihwa (also Euihwa), (born 30 March 1877 – 15 August 1955) was the fifth son of Emperor Gwangmu of Korea and his concubine, Lady Yang, who was a court lady-in-waiting. Prince Yi Kang was not the Crown Prince, even though he was older than his brother Prince Imperial Yeong, due to the status of his mother.
He was only recognized as a legitimate prince with the name of Yi Kang and was titled Prince Uihwa with the style of His Royal Highness in 1891 following a decree issued by his father. He married Lady Gim Sudeok, later known as the Princess Duk-in (22 December 1880 – 14 January 1964), a daughter of 1st Baron Gim Sajun.
Education and early life
Prince Yi Kang was appointed special ambassador to the Empire of Japan for the celebration ceremonies fpr Japan's victory in the First Sino-Japanese War of 1894-1895. The next year, he visited six European countries as an ambassador extraordinary: the United Kingdom, Germany, France, Russia, Italy and Austria. In 1899, he studied for a year at Keio University in Tokyo. He was promoted to the rank of Prince Imperial Eui, and styled His Imperial Highness the same year. In 1900, he went to the United States and began studies at Roanoke College in Salem, Virginia from March 1901, where he majored in mathematics. After graduation, he spent a brief period at the Wesleyan University in Delaware, Ohio, and then travelled to San Francisco and Hawaii, returning to Korea in 1905. While in the United States, he scandalized the Korean government with his profligate spending and playboy lifestyle.
Prince Yi Kang served as the president of the Korean Red Cross from 1906 to 1910.
Under Japanese rule
Following the abdication of King Gojong in 1907, and the Japan-Korea Treaty of 1910 by which Korea was annexed to the Empire of Japan, Prince Yi Kang grew increasingly dissatisfied with his status, even though the Japanese provided him with a huge annual allowance.
In 1919, he collaborated with Choe Ikhwan, a member of Daedongdan, who attempted to support him as the new leader of Korea. Prince Yi Kang then tried to escape to the Provisional Government of Korea based in Shanghai, which was only lukewarm to receiving him due to their republican sympathies. Prince Yi Kang was discovered in Dandong Manchuria and returned to his home country. After this, he cooperated and supported the Japanese government's occupation of Korea, and had continued this support until the end of the war.
After the independence of Korea, he continued to live in Seoul, but in increasing poverty. On August 9, 1955 he was baptized a Roman Catholic, given the Christian name of Pius, and died a week later on August 15, 1955, at the age of 78, at Seongrak Manor, Seongbuk-dong, Seongbuk-gu, Seoul, South Korea and is buried at Hongyu-reung in Namyang-ju near Seoul.
Prince Yi Gang, a man with an active personality and handsome features, had 14 concubines in addition to his official wife, Princess Duk-in. He had a total of 12 sons and 9 daughters.
- Yi Geon (이건 李键i geon) (1909–1991), his 1st son with his concubine, Lady Sugwan; m. Miss Matsudaira Yoshiko, a daughter of Captain Matsudaira Yutaka and his wife, a daughter of Marquis Nabeshima Naohiro, a maternal grandfather of Princess Bangja of Korea. He became a citizen of Japan in 1947.
- Yi Wu (이우 李鍝 i u) (1912–1945), his 2nd son with his concubine, Lady Suin; m. Lady Park Chan-ju, a granddaughter of Marquis Park Yeonghyo who was husband of Princess Yeonghye of Korea, a daughter of King Cheoljong. He was adopted by Prince Heung, his father's first cousin, so he inherited the Unhyeon Palace with a title of Prince Heung.
- Yi Bang (이방 李鎊 i bang) (1914–1951), his 3rd son with his partner, Cho Byungsuk.
- Yi Chang (이창 i chang) (1915-?), his 4th son with Cho Byungsuk. (Died in the United States.)
- Yi Ju (이주 李鑄 i ju) (1918–10 December 1982), his 5th son with Lady Suin.
- Yi Gon (이곤 李錕 i gon) (1919-1984), his 6th son with Lady Suin. He inherited the Sadong Palace after death of Prince Yi Kang.
- Yi Gwang (이광 李鑛 i gwang) (1920–1952), his 7th son.
- Yi Hyun (이현 李鉉 i hyeon) (1922–1996), his 8th son with his concubine, Lady Sugyung. He was adopted into the Gyedong Palace.
- Yi Gap (이갑 李鉀 i gap) (born 1938), his 9th son. Some members of the Yi Family Council chose his eldest son, Yi Won as the next head of Korean Imperial Household and they also made his title the Hereditary Prince Imperial (Hwangsason) in the meaning of inherited a title of Prince Gu (born 29 December 1931 – 16 July 2005).
- Yi Seok (이석 李錫 i seok) (born 1940), his 10th son with his partner, Hong Jeongsun. He is living in Jeonju, Korea and currently a professor of history, lecturing at University of Jeonju in the Korea.
- Yi Hwan (이환 i hwan) (born 1944), his 11th son with his partner, Kim Hyesu.
- Yi Jung (이정 i jeong) (born 1947), his 12th son with Hong Jeongsun.
- Yi Haewan (이해완 i hae wan) (1915–1981), his 1st daughter with his concubine, Lady Sudeok.
- Yi Haewon (이해원 李海瑗 i hae won) (born 1919), his 2nd daughter with Lady Sudeok. She claimed to be the 30th Head of the Imperial House of Korea on 29 September 2006. 
- Yi Haechun (이해춘 i hae chun) (born 1920), his 3rd daughter with his concubine, Lady Sugwan.
- Yi Haesuk (이해숙 i hae suk) (1920-?), his 4th daughter with his concubine, Lady Sugil.
- Yi Haegyeong (이해경 李海瓊 i hae gyeong) (born 1930), his 5th daughter with his partner, Gim Geumdeok. She was (now retired) a librarian for Korean studies at the Starr East Asian Library in Columbia University, New York, and is also the author of a number of royal biographies.
- Yi Hoeja (이회자 i hoe ja) (born 1940), his 6th daughter with Kim Hyesu.
- Yi Haeran (이해란 i hae ran) (born 1944), his 7th daughter with Hong Jeongsun
- Yi Haeryeon (이해련 i hae ryeon) (born 1950), his 8th daughter with Hong Jeongsun.
- Yi Changhui (이창희 i chang hui) (born 1953), his 9th daughter with Kim Hyesu.
Titles, styles, and honours
Titles from birth to death
- His Royal Highness Prince Kang of Korea (1877–1891)
- His Royal Highness Prince Euihwa of Korea (eui hwa gun ma ma) (1891–1899)
- His Imperial Highness The Prince Imperial Eui of Korea (eui chin wang jeon ha) (1899–1955)
- Grand Order of the Golden Measure and the Auspicious Stars (8 April 1906)
- Grand Cordon of the Order of the Rising Sun, 1st Class with Paulownia Flowers (3 May 1906)
- Grand Cordon of the Order of the Sacred Treasure-circa 1906
- Grand Cordon of the Supreme Order of the Chrysanthemum (8 January 1924)