X1 was a South Korean boy group formed by CJ ENM through the Mnet reality competition show Produce X 101. The group was composed of eleven members: Kim Yo-han, Kim Woo-seok, Han Seung-woo, Song Hyeong-jun, Cho Seung-youn, Son Dong-pyo, Lee Han-gyul, Nam Do-hyon, Cha Jun-ho, Kang Min-hee, and Lee Eun-sang. The group debuted on August 27, 2019 with the single "Flash" under Swing Entertainment and was co-managed by Stone Music Entertainment.