Sechskies is a six member South Korean boy band that includes what South Korean rapper whose first solo single was "A-Ha"?
Eun Ji-won: Eun Ji-won (born June 8, 1978) is a South Korean rapper, host, dancer, composer and leader of the first generation idol group SechsKies (젝스키스). Eun Ji-won:  After the group's disbandment in 2000, Eun pursued a solo career in 2001 with his first single ("A-Ha") and has mainly focused on hip-hop ever since.
i don't know