The campus expanded in the 1920s adding a girls' dormitory and Memorial Hall. On newly purchased land on Nagamine Heights, the Duke of Gloucester dedicated a boy's dormitory, Gloucester House, named in his honor in May 1929. The Latin Motto of "Scientia Clavis Successus," knowledge is the key to success, was chosen in 1921 as was the school song. The school housed refugees from the Great Kanto Earthquake of 1923.