Key signature
![Key signature A major / F♯ minor with three sharps placed after the clef.](/Images/godic/202502/01/A-major_f-sharp-minor.svg0553.png")
![Circle of fifths showing major and minor keys and their signatures](/Images/godic/202502/01/Circle_of_fifths_deluxe_4.svg0553.png")
![Bach Cantata 106 is almost entirely in E-flat major, but has only two flats, not three, in the key signature Play](/Images/godic/202502/01/GottesZeit0553.png")
![](/Images/godic/202502/01/Treble_clef_with_empty_staff.svg0553.png"){kind=spacer}
In musical notation, a key signature is a set of sharp or flat symbols placed together on the staff. Key signatures are generally written immediately after the clef at the beginning of a line of musical notation, although they can appear in other parts of a score, notably after a double barline.