Pronounced yu gai (falling tone), same pronunciation as "ai". It is the same as the character "ai". In "Xie Huilian's 'Ode to Snow' (Xie Huilian · Xue Fu)", there is a sentence "lian fen lei gai". The annotation explains: the character "gai" is pronounced "yi qie". Other detailed explanations can be found in the notes for the character "ai".