What key is the musical piece " One More Night written in ?
However , it is only a notational convenience ; a piece with a one - sharp key signature is not necessarily in the key of G major , and likewise , a piece in G major may not always be written with a one - sharp key signature ; this is particularly true in music of the Baroque and earlier , when the concept of key had not been developed , and in minor keys , which typically require accidentals even with a matching key signature .