Japan occupied Korea as a colony from 1910 to 1945. South Korean musicians have been successful in Japan since the inception of Korean popular music. There have been a number of ethnically South Korean singers who have gained fame in Japan. Some of these singers, including Choi Gyuyeop/Hasegawa Ichiro and Yi Nan-yong/Oka Ranko were Zainichi, Koreans with Japanese residency. Among these Zainichi artists, there were and still are some who have made public declarations of their Korean descent, and many more who were rumored to be Korean but have never made formal confirmations. Those who do divulge their heritage often do so after they have attained a relatively stable level of popularity. The act of revealing one's Korean ethnicity is called “coming out.” Nevertheless, there were South Korean singers like Cho Yong-pil and Kye Un-seuk, in the 1970s and 1980s who were household names in Japan, despite not being Zainichi. Today, there are also a number of non-Zainichi Korean artists such as BoA, Crystal Kay, TVXQ, BIGBANG, KARA, and BTS who have found chart and album success in Japan.
Many Korean singers who were famous in Japan sang trot music, an older genre of Korean pop music. This is partly because of trot's similarity to enka, a popular Japanese genre that resembles traditional Japanese music. The similarity between Japan's and South Korea's soundscape was due to stricter Japanese political control in the 1930s, when Japan taught Japanese shoka, Japanese-style Western music for children, in Korean elementary schools.
In terms of popular music, or "yuhaengga" in Korean, many early hits were Japanese songs that had been translated into Korean. Nevertheless, many Koreans still contributed their own unique touch to the emerging field of pop music in Korea. For example, Japanese popular-music composer Koga Masao, who had grown up in colonial Korea, incorporated Korean elements like the use of three beats to create the Korean influenced "Koga melody."
Zainichi Korean singers
Choi Gyuyeop/Hasegawa Ichiro
Known as the first Korean pop singer to advance into the Japanese market, Choi Gyuyeop sang the translated version of "Arirang," a famous Korean folk song, under the Japanese stage name "Hasegawa Ichiro." By 1932, Gyuyeop was a star in Japan, and in 1933, he held a successful Japanese tour. In 1935, he was voted the most popular singer in South Korea.
Yi Nan-yong/Oka Ranko
Yi Nan-yong began her career as a singer at a movie theater during the first wave of "yuhaengga." She attained fame through various hits including "Mok'po ui nunmul" and duets with "Emperor" Nam In-su. In 1936, she achieved success in Japan under the stage name "Oka Ranko." By the 1940s, she was participating in the Japanese war effort and was a part of the K.P.L Akdan (K.P.K Musical group), which performed for US troops. Yi later trained her children as musicians and formed the Kim Sisters, a Korean born American singing trio who successfully crossed over into the American market in the 1950s and 1960s.
Akiko Wada
Born as Kim Bok-Ja, Akiko Wada has risen as a popular Japanese singer and television performer. She made her debut as a singer in 1968, and has had a series of hits over the years, including "Doushaburi no Ame de" (In the Pouring Rain), "Furui Nikki" (Old Diary), and "Datte Shoganai Ja Nai" (Nothing You Can Do About It). She has been given the nickname "Akko" and is known for her height, more masculine appearance and unique singing voice.
Non-Zainichi Korean singers
Cho Yong-pil
In the 1980s and 1990s, Cho Yong-pil, one of the most famous Korean male singers in Korean pop and trot history, established a strong fan base in Japan. His 1980 trot debut, "Come Back to the Pusan Harbor" performed especially well in Japan. During his Japanese career he received multiple awards and held many concerts in the country. In 1987, 1998 and 1990, he also performed at NHK Kouhaku Uta Gassen, the most prestigious annual music show in Japan.
Crystal Kay
Born and raised in Yokohama, Japan to an African-American father and Korean mother, Crystal Kay debuted as a singer at the age of 13 in 1999. She has since released 11 albums, and a number of her albums, including Almost Seventeen (2002), was certified platinum by the Recording Industry Association of Japan. As of 2009, she has sold over two million records domestically and has appeared in a number of films.
Crystal Kay has discussed her nationality and race before, commenting "I consider myself a Japanese artist because I was born and raised here, but nationality-wise I look, and am, foreign."