Why music feels at home on one particular note - and how the keys relate to each other.
Back to the Music MapKey lens: Coloured: the seven notes of A major or A minor – whichever the backing plays; faint: the five that don't belong. Tap a note - this is where you'll see what it means.
It applies to the whole page - every section below works from it.
The circle of fifths at the bottom lets you pick the same root from there.
Try it
Both buttons play the same major scale upwards. One of them stops a single note earlier than the other - nothing else differs.
Listen to the left one first. It stops on the note right below the target, and you find yourself waiting for the next one.
Ends a semitone below the root. Sounds open, like a sentence broken off halfway.
Takes the one remaining step up to the root. Sounds finished.
The eight degrees of the scale
Home: 1 · 8
What do you notice?
Which of the two runs sounds finished – and what are you waiting for in the other one?
What it's called
Root (tonic) – the note where everything feels resolved – the home of a key.
Why
The note where it feels finished is C. It is the home of this key - and that is all the term means.
Home means: everything feels resolved when it arrives at that one note. A melody may wander far away from it, but as long as it has not come back, it sounds unfinished. That note is called the root, or the tonic.
This is not a convention you have to memorise - you can hear it: the same scale twice, once without and once with the final step.
The pages before this one supplied the building blocks: twelve notes, the distances between them, and scales as patterns made from those distances. A key says which of those patterns is in force right now - and above all, which note is home.
Quick check
Where does the open run stop?
Try it
First listen to all twelve notes going up, then only the seven of C major. In the circle you can tap each note on its own.
What do you notice?
Which run sounds like music – and which like sliding, with every note equally important?
What it's called
Scale – the selection of seven of the twelve notes, ordered from the root – the material of a key.
Why
Of the twelve notes a key uses seven. The other five are called outside the key: they sound as if they belonged somewhere else – in the Workshop above they are faint.
In the circle the selection becomes a shape: the seven aren't spread evenly, there are two narrow spots. That's exactly where the half steps are – the next section is about them.
Why seven? Every scale of a key uses each of the seven letters from C to B exactly once – more on that below under key signatures. There are also scales with only five notes, the pentatonics: they leave out the half steps and therefore sound good over almost anything.
Quick check
How many of the twelve notes do NOT belong to a major key?
Try it
What do you notice?
The steps are equally wide but not equally high. Where are the small steps – and can you hear them?
What it's called
Whole step and half step (whole tone, semitone) – two frets or one: the two step sizes a scale is made of.
Why
Major always climbs the same way: whole, whole, half, whole, whole, whole, half. The half steps lie between the 3rd and 4th and between the 7th and 8th degree.
Because the pattern stays the same, every major key sounds the same – just higher or lower. On a single guitar string it's 2, 2, 1, 2, 2, 2, 1 frets.
Minor uses the same two step sizes in a different order – the next section compares them on one ruler.
Quick check
Between which degrees are the half steps in major?
Try it
Listen to both in turn. The difference is already there at the third degree, long before the scale is over.
Distance from the root in semitones
What do you notice?
Same root, same start – from which note on does the second scale sound different?
What it's called
Mode (major and minor) – whether a key sounds bright (major) or dark (minor) – decided above all by the third degree.
Why
Same root, same home - and yet two completely different moods. The difference sits in just three of the seven degrees.
Degrees 3, 6, 7 differ. Each of them sits exactly one semitone lower in minor.
The third degree decides it. It arrives so early that after two notes you already know where you stand - everything after that only confirms it.
Two things tell keys apart: which note is home, and whether the pattern around it is major or minor. Everything else follows from that - including how many accidentals a key has.
Minor comes in two further versions, and there are the modes and the pentatonics as well.
See all twelve in the explore areaQuick check
Which degree is the first to give away major or minor?
Try it
What do you notice?
Both runs arrive home. In which one does the second-to-last note pull upwards more strongly?
What it's called
Leading tone – the seventh degree when it lies only a semitone below the root – it leads you home.
Why
In major the seventh degree lies a semitone below the root. So close that your ear already hears the last step – that's the pull that made the open run above sound so unfinished.
In natural minor it's a whole step. The ending therefore sounds softer and less compelling.
That's why the seventh degree is often raised in minor – which gives you harmonic minor with a real leading tone.
See all twelve in the explore areaQuick check
In which scale does the seventh degree lie only a semitone below the root?
Try it
What do you notice?
Both rows use the same seven notes. What is different anyway?
What it's called
Relative key – the major and the minor key with the same notes but a different home.
Why
The relative minor starts on the sixth degree of the major key, a minor third below its root. Same notes, same key signature – only the home moves, and with it the mood.
That's why both sit in the same place in the circle of fifths below: the major key outside, its relative minor inside.
Quick check
Which minor key shares its notes with G major?
Try it
C major: root on the low E string, fret 8.
What do you notice?
Choose a different root above. What happens to the pattern on the fretboard?
What it's called
Position – a stretch of four or five frets in which all notes of a scale fit under your hand.
Why
The pattern is the same for every major key – it just moves along the neck with the root. If you know one position, you know it in all twelve keys.
The dots in the root colour are home: from them you find your way around.
Across the whole neck there are five such positions that fit seamlessly together – the CAGED system shows how.
To the CAGED systemQuick check
You move the position two frets towards the body. What changes?
Try it
G major, each letter once – once with natural notes only, once with an accidental.
1 sharp: F#
What do you notice?
Both runs use each letter once. Which one sounds major – and where does the other stumble?
What it's called
Key signature – a sharp (♯) raises a note by a semitone, a flat (♭) lowers it.
Why
Natural notes are the seven notes without sharps or flats – the white keys on a piano. Every major scale uses each of the seven letters exactly once and follows the pattern whole, whole, half.
From G the natural notes almost fit: only between E and F is there a half step where a whole step belongs – and the half step before the root is missing. So F becomes F#. That's the one sharp of G major.
How many sharps or flats a key needs depends only on its root. The circle of fifths in the next section orders the keys exactly by that.
Quick check
Why does G major have a sharp?
Try it
Major keys on the outside, their relative minor on the inside - both use the same notes and therefore have the same accidentals. Tap one to select it.
Major · Minor
No accidentals - natural notes only.
At the bottom of the circle both paths meet: six steps forward and six steps back land on the same note. That one key has two equally valid names - the version with six sharps is the one shown here.
What do you notice?
Tap your way round clockwise. What changes from one key to the next?
What it's called
Circle of fifths – the twelve keys in a circle, each a fifth above the previous one – neighbours differ in exactly one note.
Why
Twelve keys in a circle, each one a fifth above the last. Going clockwise collects sharps; going anticlockwise collects flats.
That's why neighbours in the circle sound related: they share six of their seven notes. When a song changes key, it usually moves just one step.
Why fifths? Seven semitones and twelve have no common divisor – in steps of a fifth you hit each of the twelve keys exactly once before arriving back at the top.
Quick check
How many sharps does D major have?