Editing Relative key (section)

{{Short description|Major and minor scales with same key signature}}
In [[music]], 'relative keys' are the [[major scale|major]] and [[minor scale]]s that have the same [[key signature]]s ([[enharmonic]]ally equivalent), meaning that they share all of the same notes but are arranged in a different order of [[whole step]]s and [[half step]]s. A pair of major and minor scales sharing the same key signature are said to be in a '''relative relationship'''.<ref name="B&S">{{cite book|last1=Benward |last2= Saker |date=2003|title=Music in Theory and Practice|volume=I|pages=33–35|publisher= McGraw-Hill |isbn=978-0-07-294262-0|quote=D flat major and a minor scale that have the same key signature are said to be in a ''relative relationship''.}}</ref><ref>{{cite book|author-link=Allen Forte|last=Forte|first= Allen|date=1979|title=Tonal Harmony|page=9|edition= 3rd |publisher= Holt, Rinehart, and Wilson|isbn=0-03-020756-8|quote=The key which shares the same key signature but not the same first degree with another scale is called ''relative''. Thus, e.g. the relative of C major is A minor (no sharps or flats in either key signature); the relative major of A minor is C major.}}</ref> The '''relative minor''' of a particular major [[key (music)|key]], or the '''relative major''' of a minor key, is the key which has the same [[key signature]] but a different [[Tonic (music)|tonic]]. (This is as opposed to [[Parallel key|''parallel'' minor or major]], which shares the same tonic.)

For example, F major and D minor both have one flat in their key signature at B♭; therefore, D minor is the relative minor of F major, and conversely F major is the relative major of D minor. The tonic of the relative minor is the [[submediant|sixth]] scale degree of the major scale, while the tonic of the relative major is the [[mediant|third]] degree of the minor scale.<ref name="B&S"/> The minor key starts three semitones below its relative major; for example, A minor is three semitones below its relative, C major.

[[File:Circle of fifths deluxe 4.svg|thumb|right|350px|Circle of fifths showing major and minor keys]]

The relative relationship may be visualized through the circle of fifths.<ref name="B&S"/>

[[File:Relative tonic chords on C and a.png|thumb|350px|right|Relative tonic chords on C and A ({{audio|Relative tonic chords on C and a.mid|Play}}).]]

[[File:Chromatic modulation in Bach BWV 300, m. 5-6.png|thumb|right|350px|[[Chromatic modulation]] in Bach's ''Du grosser Schmerzensmann'', BWV 300, m. 5-6 ({{audio|Chromatic modulation in Bach BWV 300, m. 5-6.mid|Play}} with [[half cadence]], {{audio|Chromatic modulation in Bach BWV 300, m. 5-6 with resolution.mid|Play}} with PAC) transitions from FM to its relative minor dm through the inflection of C{{music|natural}} to C{{music|sharp}} between the second and third chords. This modulation does not require a change of key signature.]]

[[File:Relative major and minor scales on C and a.png|thumb|Relative major and minor scales on C and A with shared notes connected by lines.]]

Relative keys are a type of [[closely related key]]s, the keys between which most [[modulation (music)|modulations]] occur, because they differ by no more than one accidental. Relative keys are the most closely related, as they share exactly the same notes.{{sfn|Benward|Saker|2003|p=243}}
The major key and the minor key also share the same set of chords. In every major key, the triad built on the first degree (note) of the scale is major, the second and third are minor, the fourth and fifth are major, the sixth minor and the seventh is diminished. In the relative minor, the same triads pertain. Because of this, it can occasionally be difficult to determine whether a particular piece of music is in a major key or its relative minor.