This post is one of a 2-part series of free basic music theory lessons on my blog, musictheoryde-mystified.com. You can see the complete list here. Please feel welcome to make a comment or ask a question.
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This lesson should really be called Relative Modes because the following applies equally to other traditional Western diatonic modes such as Dorian or Myxolydian. All these modes are relatives; they are all siblings.
First, a quick reminder about scales, keys and key signatures. You can read more on this in my beginner’s tip, Scales, Modes And Keys: What’s The Difference?
- A key is made up of a root note and a mode (such as major or minor).
- A scale is an ordered list of the notes of a key.
- A mode is the pattern of intervals from one note to the next in a scale.
- A key signature is an ordered list of the notes of a key which are sharps or flats. Those not listed in a key signature are naturals.
- Keys/scales are named after their root note and mode.
Let’s start by looking at the naturals, A to G – a key signature of 0 sharps or flats. We already know that we can play a major scale by starting on C (C major). We can also play a minor scale by starting on A (A minor). These are the original major and minor modes.
Both these scales, C major and A minor, use the same notes; the naturals, and have the same key signature (0 sharps/flats). The same is true for any key signature.
For any key signature there is one major and one minor key. We call these relative major and minor, because they share the same notes (the same key signature).
Here we can see C major and A minor.
The relationship between them can be seen by their root notes.
- If you start with A minor, it’s relative major, C major, is the 3rd scale note up from the root note.
- If you start with C major, its relative minor, A minor, is the 3rd scale note down from the root note (or, as in the above graphic, the octave of the root note, which of course is the same).
Note: When counting scale notes, we count the starting note as the first note. For example, the 3rd note up from A is C. We count A B C.
If you already have a key signature for the major it’s really easy to count scale notes to find the relative minor. From the major’s root note just count down to the 3rd letter: the key signature takes care of the sign.
Note: To find the key signature of a major key, use the cycle of fifths. See 12. Major Keys And The Cycle/Circle Of Fifths for more.
What If We Don’t Know The Key Signature?
In the graphic of C major and A minor, we can also see that the root notes of the relative major and minor scales are 3 semitones apart. If we don’t know the key signature, such as when reading chord charts, it’s important to count semitones as well as letters.
How To Find The Relative Minor
- From a major key to its relative minor, count down to the 3rd letter.
- If we don’t know the key signature, count the number of semitones between the two notes.
- If you count 3 semitones, you have the right answer.
- If you count 4 semitones, sharpen the note (if it’s a natural, add a sharp sign).
Example 1: What is the relative minor of Ab major?
- The 3rd letter down from Ab (including A itself) is F (count A G F)
- Ab is 3 semitones below F, which is the right amount.
- The relative minor of Ab major is F minor.
Example 2: What is the relative minor of A major?
- The 3rd letter down from A (including A itself) is F (count A G F)
- F is 4 semitones below A, so we have to sharpen it to make it 3 semitones below A = F#
- The relative minor of A major is F# minor.
How To Find The Relative Major
- From a minor key to its relative major, count up to the 3rd letter.
- If we don’t know the key signature, count the number of semitones between the two notes.
- If you count 3 semitones, you have the right answer.
- If you count 4 semitones, flatten the note (if it’s a natural, add a flat sign).
Example 1: What is the relative major of E minor?
- The 3rd letter up from E (including E itself) is G (count E F G)
- G is 3 semitones above E, which is the right amount.
- The relative major of E minor is G major.
Example 2: What is the relative major of Eb minor?
- The 3rd letter up from Eb (including E itself) is G (count E F G)
- G is 4 semitones above Eb, so we have to flatten it to make it 3 semitones above Eb = Gb
- The relative major of Eb minor is Gb major.
We call the interval between the root notes of the relative major and minor a minor 3rd. Don’t worry, we’ll look at interval names properly later in this course- I only mentioned it in case you’ve heard of it. In a nutshell, when we count intervals we include the fist and last notes, hence we call from A to C a 3rd. A minor 3rd is only 3 semitones, not 4.
Note: When counting the interval between two notes as letters, always include the first and last letter.
Once you know the relative major, you can use your memory of the cycle of 5ths for major scales to find the key signature.
Patterns
C major is the original major. All other major scales have the same pattern of intervals from note to note, the same mode, as C major, so whatever we can observe with C major is true for all major scales or keys. The same can be said for A minor: whatever we can observe with A minor is true for all minor scales/keys.
This is good news! Unlike the scientific method, where every instance needs to be proven, with scales we can treat any one example as universal. So much easier, and so much easier to remember. If you forget the relationship between relative major and minor, just look at the keys you know best, C major and A minor.
Know Your Key Signatures
Classical students learn the key signatures of all major and minor keys by rote, usually at primary school age, and often gradually, over the same period of time as they learn to play in these keys.
However, there are a couple of other options which we’ll look at below. I would like to add, though, that it’s definitely worth learning at least the most commonly used keys for your instrument and genre.
The Cycle Of Fifths And Relative Minor/Major
In 12. Key Signatures: Major Keys And The Cycle/Circle Of Fifths we discovered the relationships between major keys and the order of key signatures. We also looked at using a mnemonic to remember the order of major keys and their key signatures.
Potentially we could learn another mnemonic that starts on A instead of C for the minors but we don’t need to. If we know the major key of a key signature, we can find its relative minor by counting down to the 3rd note.
How To Find The Minor Key Of A Key Signature
As we saw with our earlier example, the key signature of three flats,
- Remember (or look at) the cycle of fifths to find the major key for that key signature.
- Then simply count down to the 3rd scale note to find its relative minor.
How To Find The Key Signature Of A Minor Key
You can also use this in reverse. To find the key signature of a minor scale, count 3 semitones up to the 3rd letter to find its relative major, then use the cycle of fifths to remember/look up the key signature.
- First, find the relative major by counting up to the 3rd letter.
- Check that the interval is 3 semitones. If it’s 4 semitones, flatten the note (if it’s a natural, add a flat sign).
- Now use the cycle of 5ths for major scales, either from memory or by looking below, to find the key signature.
Example: What is the key signature of G minor?
- Count up to the 3rd letter = B
- Count semitones =4
- If 4 semitones, flatten the note = Bb. The relative major of G minor is Bb major.
- Look up the relative major in the cycle of fifths (try to do this by memory): Bb major has two flats, Bb and Eb.
- The relative minor, G minor, also has two flats, Bb and Eb.
Try These…
Exercise 1:
Name the major and minor keys that have the following key signatures.
Use your memory of the Cycle of fifths or see the graphic below below to find the major key, then find its relative minor by counting down to the third note. Be sure to look at the key signature to see whether that note is a sharp, flat or natural.
Exercise 2:
Now try it the other way round. Name the key signature of the following minor keys.
B minor, C# minor, Bb minor, C minor
Answers at the end of this post.
if you’ve forgotten the cycle of fifths for major keys, here it is…
The Cycle Of Fifths For Majors And Minors
For those who just want the ultimate shortcut and have their phone on hand, have a look at The Cycle (circle) Of Fifths which shows the cycle of fifths for both major and minor keys in the same image.
How To Tell Whether A Piece Is Major Or Minor
When you see a notated part, the key signature itself doesn’t tell you whether the piece is in the major or minor key of that key signature. It is expected that the player will be able to tell, once they look at the notes.
What a player looks for is the root note. The root note is the obvious difference between relative major and minor. Once we know both the key signature and the root note, as we play, we can listen to the notes from the perspective of the intended tonality and interpret the music correctly.
So how can we tell which note is the root note?
Looking For The Root Note
In a typical piece, the root note will be evident in the first bar and again in the last bar. By evident, I mean that the note will stand out in relation to the surrounding notes. It may be the longest or strongest note, the note most repeated, or just the note that the neighbouring notes lead towards it.
This is a very broad statement and is mostly, but not always, true.
It applies to music which is familiar to the ear: music which we might describe as “musical”, “melodic” or “understandable” when we listen to it.
Note: For more detail on how to find the root note of a written part, please have a look at How Can We Tell Which Key We’re In? This post includes some short examples of what to look for.
It may seem daunting to find the root note out of 7 possible notes but it’s not as bad as all that. The vast majority of music is based on the major or minor modes (and variations of the minor, but more on that in a later post) so for most genres we only need to look for one of two possible notes, not 7. Most of the other modes are more typically used in early music or folk music and publishers of these genres often specify the mode as text, in which case we don’t need to look any further…
Once we know which two notes to look for, we can have a look at the first and last bars of the music to find which one is more prominent.
Summary
- To find the relative major of a minor key, count up to the 3rd note in the key signature.
- To find the relative minor of a major key, count down to the 3rd note in the key signature.
- When counting, don’t forget to include the note you start on in your count.
- If you don’t have a key signature, such as when reading chord charts, make sure that the two root notes are also 3 semitones apart (not 4 semitones). This may require you to use a flat or sharp sign.
- To find the key signature of a minor key, find its relative major as above and use the cycle of 5ths for major scales to find the key signature.
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NEXT LESSON: 14. The Relationships Between Keys
PART 1 CONTENTS: Basic Music Theory Course Contents
Answers
Exercise 1:
- G major and E minor
- F major and D minor
- A major and F# minor
- Ab major and F minor
Exercise 2:
- 2 # = F#, C#
- 4# = F#, C#, G#, D#
- 5b = Bb, Eb, Ab, Db, Gb
- 3b = Bb, Eb, Ab
