Complex sentence: After Sechs Kies disbanded Eun began his solo career in 2000 under the name "G1" with the single, "A-Ha", on October 27,2000.
Split into simpler sentences: After Sechs Kies ended, Eun Ji-won started his solo career in 2000 under the name G1. He first debuted with the single track "A-Ha" on October 27,2000.