Key Signature

A key signature is a set of sharps or flats that are placed at the beginning of a staff to indicate the notes that are sharp or flat for the entire composition or any particular segment.

There are two types of key signatures – sharp and flat. Each type has its own unique set of rules.

Once you understand how to read a key signature, you can quickly and easily identify which notes are sharp or flat for the entire piece. This will help you stay in tune with the music and make playing it easier.

Read the complete article now to learn more about how to read key signatures!

What Is A Key Signature?

A key signature may be defined as the arrangement of a set of sharps or flats placed on the lines or spaces of the staff at the beginning of the piece of music or when a new section requiring another key signature starts.

The sharps and flats in the key signature indicate that the notes corresponding to the particular line or space are to be raised or lowered by a semitone in every octave from the natural notes they otherwise represent.

The initial key signature is placed immediately after the clef symbol at the beginning of the first staff line. Each different scale has its own key signature. It can also be placed at the beginning of a new section represented by a double bar line if the scale changes.

Each symbol of the key signature applies to a specific pitch class. As you may be aware, a particular note out of 12 notes in Western music can be played in multiple octaves, and the collection of such notes in multiple octaves is known as the pitch class. So pitch class C is a set of C’s in all octaves.

As an example, the sharp symbol placed on the top line of the treble staff as a key signature indicates that all the F notes in that section of music are to be played as F-sharps, even if note F appears in the space between the first and second line of the treble staff.

You can override the accidental required by the key signature by placing a natural symbol before the note at specific positions if you need.

While some evidence of the use of the symbols is found in some early pieces, the system of key signatures was not fully developed until the later part of the 18th century.

Other Features of Key Signatures

Some of the features of the key signature are summarized below. We will be discussing and explaining them in our detailed discussion in the next sections.

  1. The key signature can either have flats in it or sharps, but not both together.
  2. The sharps and flats get added in an order based on the circle of fifths.
  3. Each major or natural minor scale has a key signature.
  4. There can be a maximum of seven sharps or seven flats.
  5. This results in a total of 15 key signatures in the diatonic scales, one with no sharps or flats, seven numbers with 1 to 7 sharps, and seven numbers with 1 to 7 flats.
  6. A major key and its relative minor carry the same key signature, resulting in 12 groups.
  7. Out of the 15 key signatures, 9 are formed by groups of major/minor keys without any enharmonic equivalents.
  8. Balance six key signatures are for the three groups out of twelve with enharmonic equivalents. These groups have key signatures in sharps as well as flats also.

What Is the Difference Between Key Signatures and Keys?

The key of any piece of music represents the scale around which the song or the composition is organized. A key is the harmonic center of the musical piece, with the first note of the corresponding scale acting as the tonic center in the tonal music.

It tells the player which notes or chords will be consonant with the music and allow him to improvise the notes according to the chord progressions of the song.

A key signature, as we discussed above, is a notational system that helps you identify the key of the section of the musical piece and its diatonic scale by indicating the notes with sharps or flats at the beginning of the piece. Also, using a key signature limits the use of accidentals all over the measures or bars of the musical piece.

Why Information Does a Key Signature Convey?

The obvious question is, to be useful, what information can you get from knowing a key signature of a piece of music? The simple answer is:

  1. It tells you the seven notes available to you for playing a consonant piece of music.
  2. The related scale and the associated consonant chords.
  3. The key signature, coupled with the first few bars of the music, will tell you whether the music is in a major or a minor key. As stated earlier, the relative scales share the same notes and hence the same key signature.

How to Read Key Signatures in Music

Let us start by organizing the key signatures into four groups, as presented below. This will allow you to read and co-relate the key signatures easily with the corresponding relative scale pairs. Please look at the circle of the Fifths diagram shown below.

Circle of Fifths

We can consider it to be representing the twelve hours in a day like a clock.

The four groups of Key Signatures

  1. The 1st Group: The C Major scale showed at 12 ‘O clock position along with A minor forms the first relative scale group with no accidentals.
  2. The 2nd Group: G, D, A, and E major lying between 1 ‘O clock to 4 ‘O clock positions, forms the second relative scale group with 1 to 4 sharps. The number of sharps increases clockwise as we move from C to G, G to D, D to A, and A to E. As you know, we move up a 5th in the clockwise direction.
  3. The 3rd Group: F, Bb, Eb, and Ab major lying between 11 ‘O clock to 8 ‘O clock positions, forms the third relative scale group with 1 to 4 flats. The number of flats increases in the anticlockwise direction as we move from C to F, F to Bb, Db to Eb, and Eb to Ab. As you know, we move down a 4th in the anticlockwise direction.
  4. The 4th Group: B/Cb, F#/Gb, and Db/C#, lying between 5 ‘O clock to 7 ‘O clock positions, forms the fourth relative scale group. As you can see, each member in the group is represented by two enharmonically equivalent notes. Notes B, F#, and C# represent 5, 6, and 7 sharps. At the same time, the notes Cb, Gb, and Db represent 7, 6, and 5 flats. The number of sharps increases in the clockwise direction up to C #, and the number of flats increases in the counterclockwise direction up to Db.

Hence if you see four sharps, the relative group is E major/C# minor at the 4’O Clock position. Or if you encounter five flats, the relative scale group is Db Major/Bb minor at the 7’O clock position.

We will see it in a little more detail in the next sections.

Key of C Major and A Minor

As stated earlier, the C Major key and its relative A minor key are the only relative key pair that does not have any sharps or flats. It belongs to group 1, defined above.

Sharp Key Signatures

In this section, we will discuss the key signatures having only sharps, i.e., groups 2 and 4 above from 1′ O clock position to 7 ‘O clock position in a clockwise direction.

Major Key Signatures with Sharp Keys only

The table below shows the above 7 scales, their relative minors, and the notes of the major scale. SD denotes the scale degree of the notes of the scales, as per the music theory.

Major Scale notes - Key Signatures with Only Sharps

The important observations from the above table are:

  1. The scales are in the order they appear on the circle of fifths in the clockwise direction.
  2. One sharp note gets added to each scale as we move clockwise.
  3. In group 2 – G Major / E minor has one sharp, D Major / B minor has two sharps, the A Major / F# minor has three sharps, and E Major / C# minor has four sharps.
  4. In group 4 – B Major / G# minor has five sharps, the F# Major / D# minor has six, and C# Major / A# minor has all seven notes with sharps.
  5. The new sharp note gets added in the 7th scale degree of the major scale, at the major 7th interval, which is only one-half step below the octave of that scale. For example, in the G Major scale, the scale degree seven is F, so the scale has only one sharp note, the F#.
  6. You may also note that F is the note two steps in the anti-clockwise direction on the circle of 5ths from G. This pattern is true for the addition of sharps for all the subsequent scales/notes.
  7. The sharp note, once introduced, continues in the following scales, which means the D major scale will have two sharps, F# from the previous key and a new sharp note – at the M7 interval from D, half step below D, i.e., C#. Note that the C note is two steps before D in the anti-clockwise direction.
  8. The order of sharps, which is the order in which the sharp notes get added to the major keys, are F, C, G, D, A, E, and B. These notes lie between 11′ O clock to 5′ O Clock positions on the circle of fifths in the clockwise direction in a sequence.

Minor Key Signatures

The minor key signatures with only the sharps are shown in the table below with their notes. They can just be derived by knowing the notes of their relative major scales.

Minor Scale notes - Key Signatures with Only Sharps

Flat Key Signatures

In this category, the key signature consists of flat symbols only, ranging from one to seven flats in increasing order as you move from the 11 ‘O clock position to the 5 ‘O clock position anti-clockwise. They cover groups 3 and 4, defined above.

Major Key Signatures with Flat Keys only

The table below shows the major and relative minor scales with only flat signatures, along with the notes of the major scales.

The important observations from the above table are:

  1. The scales are in the order they appear on the Circle of Fifths in the anticlockwise direction, starting with the key of F Major.
  2. One flat gets added in each successive key as we move counterclockwise.
  3. In Group 3 – the F major / D minor has one flat, the B flat major / G minor has two flats, E flat major / C minor has three flats, and the A flat major / F minor has four.
  4. In Group 4 – Db Major / Bb minor has five flats, Gb Major / Eb minor has six, and Cb Major / Ab minor has all its seven notes with flats.
  5. Once a flat note is added, it continues in the next keys in the order.
  6. For any scale, the new flat always gets added to the note at the scale degree 4 of the major scale.
  7. You may observe the different key signatures in this table and also note that the newly added flat note is also the tonic note of the next scale in the order.
  8. The order of the addition of flats is Bb, Eb, Ab, Db, Gb, Cb, and Fb, i.e., a separation of 5 semitones or a Perfect 4th from the previous note.

Minor Key Signatures

Similar to the exercise with sharps, you can know the notes of the minor keys by notes of their relative majors and their key signatures. They are shown in the table below.

Minor Scale notes - Key Signatures with Only Flats 02

Key Signature Chart

The below table shows the key signature charts for both the sharps and the flats categories, with the key signatures shown on the treble clef.


Thanks for reading! We hope you now have a better understanding of what key signatures are and how to read them. Please provide any comments you may have in the section below – we would love to hear from you!

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