About Yui Kobayashi
Yui Kobayashi, also known as Yousti, is a Japanese singer and model. She is a former member of the idol group Sakurazaka46. She is represented by Sony Music Records and is an exclusive model with a fashion magazine with. On August 21, 2015, Kobayashi along with 22 other members was announced for the newly created idol group Toriizaka46, later renamed to Keyakizaka46 and currently known as Sakurazaka46. Kobayashi made her musical debut with Keyakizaka46's first single, Silent Majority. She held performance center roles typically held by Yurina Hirate when Hirate was unavailable, including the 60th Japan Record Awards and the 69th NHK Kōhaku Uta Gassen.
Biography source: Wikipedia. The profile adds birthday-specific historical context from the Celebs Birthday Today editorial database.