1the9

1the9 (Korean: 원더나인, stylized as 1THE9, pronounced as "Wonder Nine") was a South Korean boy band formed through the 2018 survival competition Under Nineteen. The group was composed of 9 members: Yoo Yong-ha, Kim Tae-woo, Lee Seung-hwan, Shin Ye-chan, Kim Jun-seo, Jeon Do-yum, Jung Jin-sung, Jeong Taek-hyeon and Park Sung-won. The group's debuting members were announced on February 9, 2019 and was initially slated to be promoting under PocketDol Studio for 12 months. After delays surrounding the COVID-19 pandemic, the group disbanded in August 2020.

1THE9 was formed through the 'survival' competition series Under Nineteen, which aired on MBC from November 3, 2018 until February 9, 2019. Out of an initial 57 trainees participating, the final 9 were chosen by the audience voting and announced via live television broadcast.

During the final broadcast the final members were ranked and marked to debut by votes from the fans. It was announced that the final lineup would do a V Live to thank the fans two hours after the show as well as their name. It was later announced that vocal team director Crush would be writing and producing the groups debuting single.

Although their official debut is scheduled for April, they will be participating in "Under Nineteen's Final Concert" on February 23, 2019 performing songs from the show with the other contestants. Since the show, the members have performed the single "Like a Magic" on music shows and has used it as a pre-debut promotion single.

On February 22, 2019, it was announced that their official debut was set for April 12 with a concert later on in the month with their Japan debut. It was also announced that a reality show for the group will begin airing on March 22. Their Japan debut was put on hold due to MBK wanting to focus on promotions in South Korean first.

A series of individual teasers was released per member before the debut timeline was announced. On April 5 the debut timeline started and the name of the album was revealed to be XIX with the title track being "Spotlight". A pre-debut track "Domino" featuring Crush was released on April 7 leading up to their official debut on April 13. 1THE9 began promoting the album with "Spotlight" on various music shows.

On April 17, they held their debut stage through a V Live special for an hour and thirty minutes. They performed 3 songs, played games, and announced the fandom name and color to be Wonderland and Lime Punch, respectively.

On October 3, 2019, it was announced that they would return with their second mini-album Blah Blah on October 17.

On July 6, 2020, it was announced that they would release their third mini-album Turn Over on July 16.

On July 27, 2020, it was confirmed that the group would officially disband on August 8. Before their disbandment, the group released their final EP Good Bye 1the9 on August 5.

• Yoo Yong-ha (유용하) - leader
• Kim Tae-woo (김태우)
• Lee Seung-hwan (이승환)
• Shin Ye-chan (신예찬)
• Kim Jun-seo (김준서)
• Jeon Do-yeom (전도염)
• Jung Jin-sung (정진성)
• Jeong Taek-hyeon (정택현)
• Park Sung-won (박성원)

• Under Nineteen Final Concert

• 1THE9 on Facebook