A natural minor scale shares exactly the same notes as its relative major, but begins on the sixth degree of that major scale. The interval pattern for a natural minor scale is W-H-W-W-H-W-W. The simplest example is A natural minor, spelled A B C D E F G A, which has no sharps or flats and serves as the relative minor of C major. This relationship between major and minor scales is one of the most important concepts in tonal music.
From A minor, other natural minor scales extend in both directions of the circle of fifths. E natural minor has one sharp (F♯), spelled E F♯ G A B C D E, and is the relative minor of G major. D natural minor contains one flat (B♭), spelled D E F G A B♭ C D, and is the relative minor of F major. B natural minor has two sharps (F♯, C♯), spelled B C♯ D E F♯ G A B, as the relative minor of D major. G natural minor contains two flats (B♭, E♭), spelled G A B♭ C D E♭ F G, as the relative minor of B♭ major. C natural minor has three flats (B♭, E♭, A♭), spelled C D E♭ F G A♭ B♭ C, as the relative minor of E♭ major. F♯ natural minor has three sharps (F♯, C♯, G♯), spelled F♯ G♯ A B C♯ D E F♯, as the relative minor of A major. To find the relative minor of any major key, simply count down a minor third (three half steps) from the major key's root, or equivalently move up to the sixth scale degree.
The harmonic minor scale is a natural minor with the seventh degree raised by a half step. This raised seventh creates a leading tone that strongly resolves to the tonic, and it produces a distinctive augmented second interval between the sixth and seventh degrees. A harmonic minor, for instance, raises G to G♯ to give A B C D E F G♯ A; the augmented second between F and G♯ gives this scale its characteristic exotic sound. E harmonic minor raises D to D♯ for the notes E F♯ G A B C D♯ E, creating a strong pull toward the tonic E. D harmonic minor raises C to C♯, giving D E F G A B♭ C♯ D, where the augmented second between B♭ and C♯ imparts a Middle Eastern or Spanish flavor. The interval pattern of any harmonic minor scale is W-H-W-W-H-A2-H, where A2 represents the augmented second (three half steps) between the sixth and seventh degrees. This scale is essential in classical music because the raised seventh enables a dominant chord with major quality, making possible the strong V–i cadence that establishes a minor key.
The melodic minor scale was developed to smooth out the awkward augmented second found in harmonic minor. It raises both the sixth and seventh degrees when ascending, then reverts to natural minor (with the lowered sixth and seventh) when descending. A melodic minor ascending is A B C D E F♯ G♯ A, while descending it returns to A G F E D C B A. D melodic minor ascending raises both B♭ to B natural and C to C♯, giving D E F G A B C♯ D; descending, it reverts to D natural minor: D C B♭ A G F E D. C melodic minor ascending gives C D E♭ F G A B C, raising A♭ to A natural and B♭ to B natural; this scale differs from C major by only one note (E♭ instead of E). In jazz, the melodic minor scale uses the raised sixth and seventh in both directions, sometimes called the jazz minor scale, while classical practice raises them only ascending.