Kosuge Yu started her performance activities at the age of nine and made her recital debuts at Carnegie Hall in 2005 and at the Salzburg Music Festival in 2006. She has performed with the Berlin Symphony Orchestra, Frankfurt Radio Symphony Orchestra, Stuttgart Radio Symphony Orchestra, NDR Radiophilharmonie, St. Petersburg Symphony Orchestra, Finnish Radio Symphony Orchestra, etc. alongside famous conductors such as Alexander Dmitriev, Charles Dutoit, Ozawa Seiji, Oue Eiji, Roger Arthur Carver Norrington, and Sakari Markus Oramo. In 2010 Kosuge performed with Camerata Salzburg under the baton of Philippe Herreweghe substituting Ivo Pogorelich at the Salzburg Festival. From 2010 to March 2015, she gave concerts (eight in total) playing complete piano sonatas by Beethoven in Tokyo and Osaka. Currently Kosuge promotes Beethoven MO-DE, a new project to perform all of Beethoven's pieces on piano, in solo, chamber music and lieder with piano accompaniment. She has released more than fifteen CDs including Beethoven Klaviersonaten No.5 Botschaft from Sony. Kosuge received the 13th Nippon Steel Music Award and 17th Idemitsu Award. She also won the 64th Cultural and Education Ministry's New Artist of the Year Award in 2014 and the 48th Suntory Music Award in 2017. Kosuge held the recital series "Four Elements" focusing on "water, fire, air and earth" for four years from 2017, which gained her the highest of praise.