Major Scales and Key Signatures
Senior 2 · Music
Major Scales and Key Signatures
Lesson 3 of 5
22 min
In G major every F is played as F♯. Writing a sharp before every F in a long hymn would be slow and would clutter the page. Instead, the sharps or flats of the key are written once at the start of every line, just after the clef. This group of signs is the key signature. It tells the performer which notes are always sharp or flat, in every octave, and it is the quickest clue to the key of a piece.
Build a major scale on the dominant (5th degree) of C, which is G, and you need one sharp: F♯. Build the next scale on the dominant of G, which is D, and you keep F♯ and add C♯. Each new key starts five notes above the last one and adds one new sharp, and the new sharp is always the leading note of the new key.
The sharps are always written in the same order, F C G D A E B, and always on the same lines and spaces, as above. A memory sentence: "Father Charles Goes Down And Ends Battle".
Rule for sharp keys: the last sharp is the leading note, so the key note is one semitone above the last sharp.
Worked example
A key signature has three sharps: F♯, C♯ and G♯. The last sharp is G♯, and one semitone above G♯ is A. The key is A major. Check: A B C♯ D E F♯ G♯ A follows T T S T T T S.
Now go the other way. Build a scale on the subdominant (4th degree) of C, which is F, and you need one flat: B♭. The subdominant of F is B♭, and B♭ major needs B♭ and E♭. Each new key starts on the 4th degree of the last one and adds one flat, and the new flat is always the 4th degree of the new key.
The flats are written in the order B E A D G C F, which is the order of sharps backwards. A memory sentence: "Battle Ends And Down Goes Charles's Father".
Rule for flat keys: the second-last flat names the key. With four flats (B♭ E♭ A♭ D♭) the second-last is A♭, so the key is A♭ major. A single flat has no second-last flat, so learn it by heart: one flat means F major.
With a key signature, the notes need no accidentals beside them. Here the two sharps of D major make every F and every C sharp:
A staff with no sharps or flats at all is in C major, or in its relative minor, which you will meet in Unit 2.
Tip
Last sharp: go up a semitone. Second-last flat: read the name. Learn the two orders, F C G D A E B for sharps and B E A D G C F for flats, and you can name any major key from its signature in seconds. One flat is F major.
Try each question first, then check the worked solution underneath.
Name the major key with two flats.
Solution: B♭ major. The flats are B♭ and E♭, and the second-last flat is B♭.
Name the major key with four sharps.
Solution: E major. The sharps are F♯ C♯ G♯ D♯; the last is D♯, and a semitone above D♯ is E.
Which sharps are in the key signature of A major?
Solution: Three: F♯, C♯ and G♯. The scale is A B C♯ D E F♯ G♯ A.
Write out the key signature of E♭ major.
Solution: Three flats: B♭, E♭ and A♭. The scale is E♭ F G A♭ B♭ C D E♭.
How many sharps does B major have, and which sharp comes last?
Solution: Five: F♯ C♯ G♯ D♯ A♯. The last, A♯, is the leading note of B major.
Remember
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