The major scale
Seven notes built on the pattern tone–tone–semitone–tone–tone–tone–semitone. Every major key uses it.
The major scale is seven notes and one rule. The rule is the pattern of steps between them:
T – T – S – T – T – T – S
where T is a tone (two semitones) and S is a semitone.
C major: the pattern with no accidents
Start on C and apply the pattern and you land exactly on the white keys.
That coincidence is the only reason C major is taught first. It is not simpler; it just happens to need no accidentals.
Building a major scale from any note
Apply the same pattern from a new starting note and add whatever accidentals it takes.
G major. G, A, B, then a semitone to C, then D, E, and now the pattern needs a tone from E — which lands on F♯, not F. Then a semitone up to G.
Result: G A B C D E F♯ G — one sharp.
F major. F, G, A, then a semitone — but A to B is a tone, so the fourth note must be B♭.
Result: F G A B♭ C D E F — one flat.
Repeat this from all twelve starting notes and you have generated every key signature there is. That is genuinely all a key signature is: the accidentals a major scale needs from that starting note.
One of each letter
A major scale uses each letter name exactly once. G major is spelled with F♯, never G♭ — even though those are the same key — because a scale containing both G♭ and G would use G twice and skip F entirely, and would be unreadable on a staff.
This rule is why enharmonic spelling is not a matter of taste.
Scale degrees
Each note has a number and a traditional name:
| Degree | Name | Role |
|---|---|---|
| 1 | Tonic | Home |
| 2 | Supertonic | |
| 3 | Mediant | Sets major or minor |
| 4 | Subdominant | |
| 5 | Dominant | Strongest pull back to 1 |
| 6 | Submediant | |
| 7 | Leading tone | Leans hard into 1 |
The names for 1, 5 and 7 are the ones worth knowing. The leading tone sits a semitone below the tonic, and that semitone is most of what makes a major key sound resolved when it arrives home.
Why it is the reference point
Nearly everything else is defined against the major scale. A minor scale is described as having a flattened third, sixth and seventh. A minor seventh chord is described by which degrees it flattens. Learn this pattern properly and the rest is described in terms you already have.