Sharp key

Sharps clockwise

The page Circle of fifths gives the basic rule: if you move clockwise, the key rises by a fifth, and each new key gets exactly one more sharp. Anticlockwise each key gets one more flat. The sharp keys are therefore the right half of the circle, from G major with one sharp to C♯ major with seven.

The sharps appear, according to the page, in a key signature always in the same order: F♯, C♯, G♯, D♯, A♯, E♯, B♯. A familiar mnemonic is “Father Charles Goes Down And Ends Battle”. The page Key Signatures explains the background: both series, that of the sharps and that of the flats, are steps of fifths, upwards for the sharps, downwards for the flats.

Finding the tonic

A shortcut follows from the order. The pages Circle of Fifths and Key Signatures give the same rule: in sharp keys the tonic lies a semitone above the last sharp. If the last sharp is F♯, the tonic is G, if it is G♯, the tonic is A. If the key signature has F♯, C♯, G♯, the tonic is therefore A, and it is A major. C major without a sharp is the exception that you simply remember; F major with its flat already belongs to the flat keys.

That the tonic lies exactly a semitone above the last sharp is no coincidence: the last sharp is on the leading tone, and the leading tone lies a semitone below the tonic.

Sharp keys in the score

Two sheets from the archive show the rule in practice:

Voice with chords

• Nun danket alle Gott Johann Crüger, chorale · voice with chords · 1 page

  One sharp in the key signature (F♯), the chord symbols begin and end with G: G major, the first sharp key after C major.

Guitar

• Gitarrenschule, Stück Nr. 14 Johann Kaspar Mertz · from: Guitar-Skole · guitar · 1 page

  Three sharps in the key signature (F♯, C♯, G♯). The chord symbols name A, E7 and F♯m7, in bar 9 also E, that is, A major with its dominant and the relative F♯ minor.

The key signature alone does not yet say whether a piece is in major or minor, because every sharp key shares it with its relative key. The table names the relative each time. See Relative key.

Common mistakes

• Swapping the order of the sharps: Three sharps mean A major only if they are F♯, C♯ and G♯, in this order and on the right lines.
• Taking the last sharp for the tonic: The tonic lies a semitone above, not on the sharp itself.
• Confusing major and minor: The same sharps can also mean the relative key. The ending decides.