Two years after Seo Taiji and Boys' retirement, Taiji resumed his career as a musician and solo act, which has been and continues to be successful. He sought to return to his true roots and perform rock music. Without any appearances or activity in South Korea, he released an album with a couple of music videos in 1998. There was some controversy over his sudden reversal of retirement, but his first Solo album "Seo Tai Ji" sold more than a million copies, even without any promotion in Korea. His first solo work included heavy metal and nu metal songs, but the main genre was still alternative rock. Although it was his first solo work, fans refer to it as his 5th album.