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III.5Part III, Tonality

Key Signatures with Sharps

You'll learn to read a sharp key signature to find the key, and to write the key signature of a given key.

6 min8 questionsDanhauser § 119 to 122

The sharps that belong to a key are not written in front of every note they affect: that would clutter the page. Instead, they are placed once and for all, in their order, right after the clef at the beginning of the staff, on the lines or spaces of the notes they alter.

Placed this way, they form the key signature. Their effect lasts for the whole piece, in every octave, as long as the key signature does not change.

Key signatures from 1 to 7 sharps, always in the order F C G D A E B.

So the key signature is what tells you the key of a piece. Let's see how to read it.

From key signature to key

The last sharp always falls on the leading tone. So the tonic is the note a diatonic half step above the last sharp.

With one sharp, F#, the tonic is G.
With five sharps, the last one A#, the tonic is B.

From key to key signature

Working the other way, the last sharp falls on the degree just below the tonic. For example, take the tonic E. The last sharp is D#, a diatonic half step below E. In the order of sharps, D# is the 4th, so there are four sharps in the key of E: F#, C#, G# and D#.

E major: the key signature is enough, so no sharps are written in front of the notes.

WorkshopKey Signature QuizFull screen

Practice: find the major key for each key signature. The relative minor will come later.

Which MINOR key has this key signature?

Method: with sharps, the major tonic is a half step above the last sharp; with flats, it is the second-to-last flat (F major for one flat). The relative minor is a minor third lower.

Exercisein the method's spirit

1. Find the keys indicated by key signatures of 2, 3, 6 and 7 sharps.
2. Give the key signatures of G, F#, B and C# major.

That's it for the sharps. Next, let's build the scales with flats.

Check your understanding

8 questions

Which major key does this key signature indicate?

With one sharp in the key signature, the major key is:

How many sharps are in the key signature of B major?

The key signature of C# major has:

The last sharp of the key signature is D#. What is the major key?

Which sharps make up the key signature of D major?

A sharp placed in the key signature on the F line affects:

Six sharps, the last one E#. What is the major tonic?

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