Number_i is a trio boy group formed under Takizawa Hideaki’s TOBE MUSIC Co., Ltd.. The group consists of 神宮寺勇太 (Yuta Jinguji), 平野紫耀 (Sho Hirano) and 岸優太 (Yuta Kishi), all of whom are former members of King & Prince that left the group and their agency on 22 May 2023.

The name of the group was created by Kishi, which is also liked by the members during first impression, carries the meaning of ‘I (myself)’ ‘Only One’ and ‘Love’ (“i” pronunciation in Japanese “ai” means “Love”, and “ichi” means number No. 1); as well as the message and commitment towards their fans to walk the journey with the group. He also further explained the meaning on 2 separate occasions, one during a livestream and another during an interview:

But what’s even more important is the journey to there. How can we shine and have fan in our own way? And how much fun time can we have together with our fans? It’s a truly unique journey and experience.

I would be happy if people would know our songs first and become our fans, and we would like to become a group that can be known from various places.

The trio make their debut with “GOAT” on 1 January 2024 and held their debut live show at to HEROes ～TOBE 1st SuperLive～ in March 2024. In April 2024, they made their live US debut on Coachella 88rising stage. In May 2024, they release their debut album, No.O -ring-.

During their Ariake Arena concert, Number_i also announced their fandom name, titled iLYs, which means “(Number_i) I Love You (guy)s.”