3 Sharps: A Major / F Sharp Minor
Three sharps is A major, or F sharp minor. The sharps are F sharp, C sharp and G sharp, and a semitone above the last of them lands on A.
3 sharps
A major / F♯ minor
The last sharp written is G♯. Go up one semitone from it and you have the major key: A major.
A major scale
A B C♯ D E F♯ G♯
F♯ minor scale (relative minor)
F♯ G♯ A B C♯ D E
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A major scale
A B C♯ D E F♯ G♯
F♯ minor scale
F♯ G♯ A B C♯ D E
Reading it, and a warning about the minor
Applying the rule: the last of the three sharps is G sharp, and a semitone above G sharp is A. The major key is A. The relative minor is three semitones below, which is F sharp minor — and that is the first signature where the relative minor's tonic is itself a sharpened note.
That catches people out. It is easy to count down three semitones from A and land on F rather than F sharp, particularly when reading quickly. The check is that the minor tonic must be a note that is actually in the key: F natural is not in A major, and F sharp is, so F sharp minor it is.
The third sharp and the guitar
A major on a guitar has an open tonic — the fifth string — and the standard A chord is three fingers in one fret with two strings ringing open. Combined with E and D, which are the keys a semitone-count away on either side, A sits inside the cluster of keys the instrument handles most naturally.
F sharp minor does not. Like B minor it is a barre chord, at the second fret, and a piece in F sharp minor asks a guitarist for barre shapes more or less throughout. It is a good illustration of a general fact about the instrument: a guitar's difficulty is determined by chord shapes rather than by how many accidentals the signature contains.
Where it turns up in playing traditions
A is one of the standard keys of American old-time and bluegrass fiddling, alongside G and D. Fiddlers frequently retune for it — the cross-tuning that raises the two lowest strings to A and E, giving open drones on the tonic and the fifth, is a long-established practice in that repertoire.
On the classical side, A major is a comfortable string key for the same open-string reasons as D: the violin's open A and open E are the first and fifth degrees. It is noticeably less comfortable for flat-pitched wind instruments, where concert A becomes B for a B flat instrument (five sharps) and F sharp for an E flat instrument (six).
The scale and its chords
A major is A B C sharp D E F sharp G sharp. Three of its seven notes are sharpened, which is the point at which a signature starts to feel like it is doing real work: nearly half the scale is affected, and a player reading in this key has to hold three raised notes in mind rather than one or two.
The diatonic chords are A, B minor, C sharp minor, D, E, F sharp minor and G sharp diminished. The presence of both B minor and F sharp minor here is worth noting for guitarists — the two barre-chord keys of the previous signatures both appear as ordinary chords within this one, which is why so much guitar music in A ends up using a capo.
The seven chords of A major
Every major key produces the same pattern of chord qualities — major on the first, fourth and fifth degrees, minor on the second, third and sixth, diminished on the seventh. Only the names change.
Questions people ask about this signature
- Three sharps is what key?
- A major, or F sharp minor. The three sharps are F sharp, C sharp and G sharp.
- Why is the relative minor F sharp minor and not F minor?
- Because the relative minor's tonic has to be a note that belongs to the key, and A major contains F sharp, not F natural. Counting three semitones down from A gives F sharp.
- Is A major hard on guitar?
- The major is easy — an open A chord uses one fret and leaves two strings open. The relative minor, F sharp minor, is a barre chord, so pieces centred on the minor are considerably harder than the shared signature suggests.