The group was formed August 19, 2022 on the television program THE NEXT UP ~ Tsugi wa Kimida Yo ~ [2] and debuted February 15, 2023 with the EP "Foundations".
[5] On May 27, Ken The 390 began airing THE NEXT UP ~ Tsugi wa Kimida Yo ~ on Music Blood, planning to debut five trainees that failed the Produce 101 Japan season two audition.
[13] A crowdfunding campaign on the Japanese fundraising website Ubgoe was started April 13, promising the release of Maison B's first pre-debut single.
[15] On November 1, Maison B announced the formation of a sub-unit consisting of members RICK and REIJI named roomR, along with the release of Ken the 390's digital single Anything Goes (feat.roomR) which featured the unit.
On January 18, Maison B pre-released the music video for the title track to their EP Foundations, as well as releasing it digitally to streaming platforms.