Sung Jae-gi, South Korean philosopher and activist (b. 1967)
Sung Jae-gi (Korean: 성재기; Hanja: 成在基 [səːŋ dʑɛgi]; September 11, 1967 – July 26, 2013) was a South Korean men's rights activist and anti-feminist. Sung founded and was the first chairman of Man of Korea, a men's rights group advocating the abolition of the Ministry of Gender Equality and Family—whose Korean name (여성부; 女性部) translates as "Ministry of Women"—and demanded compensation for the South Korean military-service requirement.During the early 21st century, Sung led the South Korean anti-feminist movement opposing female-preferential policies. In early adulthood he was a businessman, and in October 1999 he participated in the movement opposing the abolition of preferential treatment for discharged soldiers. Sung also opposed the abolition of the Hoju system, and later participated in men's-rights activities. In 2006 he founded the Association of Anti-Feminism and Male Liberation, and in 2007 he founded the Association for the Abolition of the Ministry of Women. The following year, Sung founded Man of Korea and was its chairman from 2008 until his death in 2013. His business activities included a nightclub and a consulting and executive search company.

From 1999 until his death Sung argued for the restoration of the Korean Army bonus points system (군가산점 제도), and during the early 2010s he was an activist for the abolition of women-only facilities. In 2011, he began offering assistance and counseling to battered husbands, househusbands, teenage runaways and male and child victims of violent crime. Sung opened a shelter for homeless persons, male victims of violent crime, teenage runaways and gay and transgender people. From 1999 to 2013, Sung was part of the gender liberation and liberal movements and the movement to abolish the women's special-benefits policy.

Near the end of his life Sung was reportedly up to ₩100 million in debt, and on July 25, 2013 he posted on the Man of Korea website his intention to commit suicide. The next day, Sung jumped from the Mapo Bridge in Seoul. His body was found four days later.Sung wrote under the pen names Blue Wolf (Korean: 푸른늑대), Tongbalbass (Korean: 똥발바쓰) and Tongbal (Korean: 똥발), and his nickname was Shimheon (심헌 審軒 or 심헌 心軒). His family is part of the Changnyeong Sung clan (창녕성씨 昌寧成氏).