Closely related key - AbsoluteAstronomy.com

Music

Music is an art form whose medium is sound and silence. Its common elements are pitch , rhythm , dynamics, and the sonic qualities of timbre and texture...

, a closely related key is one sharing many common tone

Common tone

In music a common tone is a pitch class that is a member of, or common to, a musical scale and a transposition of that scale, as in modulation...

s with an original key

Key (music)

In music theory, the term key is used in many different and sometimes contradictory ways. A common use is to speak of music as being "in" a specific key, such as in the key of C major or in the key of F-sharp. Sometimes the terms "major" or "minor" are appended, as in the key of A minor or in the...

, as opposed to a distantly related key (or "close key" and "distant key"). In music harmony

Harmony

In music, harmony is the use of simultaneous pitches , or chords. The study of harmony involves chords and their construction and chord progressions and the principles of connection that govern them. Harmony is often said to refer to the "vertical" aspect of music, as distinguished from melodic...

, such a key shares all, or all except one, pitches

Pitch (music)

Pitch is an auditory perceptual property that allows the ordering of sounds on a frequency-related scale.Pitches are compared as "higher" and "lower" in the sense associated with musical melodies,...

with a key with which it is being compared, and is adjacent to it on the circle of fifths

Circle of fifths

In music theory, the circle of fifths shows the relationships among the 12 tones of the chromatic scale, their corresponding key signatures, and the associated major and minor keys...

and its relative majors or minors

Relative key

In music, relative keys are the major and minor scales that have the same key signatures. A major and minor scale sharing the same key signature are said to be in a relative relationship...

.

Such keys are the most commonly used destinations or transpositions

Transposition (music)

In music transposition refers to the process, or operation, of moving a collection of notes up or down in pitch by a constant interval.For example, one might transpose an entire piece of music into another key...

in a modulation

Modulation (music)

In music, modulation is most commonly the act or process of changing from one key to another. This may or may not be accompanied by a change in key signature. Modulations articulate or create the structure or form of many pieces, as well as add interest...

, because of their strong structural links with the home key. Distant keys may be reached sequentially through closely related keys by chain modulation, for example C to G to D or C to C minor to E major. For example, "One principle that every composer of Haydn's day kept in mind was over-all unity of tonality. No piece dared wander too far from its tonic key, and no piece in a four-movement form dared to present a tonality not closely related to the key of the whole series."

Given a major key

Major scale

In music theory, the major scale or Ionian scale is one of the diatonic scales. It is made up of seven distinct notes, plus an eighth which duplicates the first an octave higher. In solfege these notes correspond to the syllables "Do, Re, Mi, Fa, Sol, La, Ti/Si, ", the "Do" in the parenthesis at...

tonic (I), the related keys are:

vi (submediant
Submediant
In music, the submediant is the sixth scale degree of the diatonic scale, the 'lower mediant' halfway between the tonic and the subdominant or 'lower dominant'...

or relative minor): same key signature
IV (subdominant
Subdominant
In music, the subdominant is the technical name for the fourth tonal degree of the diatonic scale. It is so called because it is the same distance "below" the tonic as the dominant is above the tonic - in other words, the tonic is the dominant of the subdominant. It is also the note immediately...

): one less sharp
Sharp (music)
In music, sharp, dièse , or diesis means higher in pitch and the sharp symbol raises a note by a half tone. Intonation may be flat, sharp, or both, successively or simultaneously...

(or one more flat) around circle of fifths
V (dominant
Dominant (music)
In music, the dominant is the fifth scale degree of the diatonic scale, called "dominant" because it is next in importance to the tonic,and a dominant chord is any chord built upon that pitch, using the notes of the same diatonic scale...

): one more sharp (or one less flat) around circle of fifths
i (parallel minor
Parallel key
In music, parallel keys are the major and minor scales that have the same tonic. A major and minor scale sharing the same tonic are said to be in a parallel relationship...

): same tonic, different key signature

Specifically:

Major	Relative Minor	Subdominant and dominants
C	Am	F, G, Dm, Em
G	Em	C, D, Am, Bm
D	Bm	G, A, Em, Fm
A	Fm	D, E, Bm, Cm
E	Cm	A, B, Fm, Gm
B	Gm	E, F, Cm, Dm
F	Dm	B, C, Gm, Am
G	Em	C, D, Am, Bm
D	Bm	G, A, Em, Fm
A	Fm	D, E, Bm, Cm
E	Cm	A, B, Fm, Gm
B	Gm	E, F, Cm, Dm
F	Dm	B, C, Gm, Am

Another view of closely related is that there are six closely related keys, based on the tonic and the remaining triads of the diatonic scale, excluding the dissonant leading-tone diminished triad. Four of which differ by one accidental, one with the same key signature, and the parallel modal form. In the key of C major these would be: D minor, E minor, F major, G major, A minor, and C minor.

In modern music, the closeness of a relation between any two keys or sets of pitches may be determined by the number of tones they share in common, which allows one to consider modulations not occurring in standard major-minor tonality. For example, in music based on the pentatonic scale

Pentatonic scale

A pentatonic scale is a musical scale with five notes per octave in contrast to a heptatonic scale such as the major scale and minor scale...

containing pitches C, D, E, G, and A, modulating a fifth higher gives the collection of pitches G, A, B, D, and E, having four of five tones in common. However, modulating up a tritone

Tritone

In classical music from Western culture, the tritone |tone]]) is traditionally defined as a musical interval composed of three whole tones. In a chromatic scale, each whole tone can be further divided into two semitones...

would produce F, G, A, C, D, which shares no common tones with the original scale. Thus the scale a fifth higher is very closely related, while the scale a tritone higher is not. Other modulations may be placed in order from closest to most distant depending upon the number of common tones.

Another view in modern music, notably in Bartok, a common tonic produces closely related keys, the other scales being the six other modes. This usage can be found in several of the Mikrokosmos piano pieces.

When modulation causes the new key to traverse the bottom of the circle of fifths this may give rise to a theoretical key, containing eight (or more) sharps in its notated key signature; in such a case, notational conventions require re-casting the new section to its enharmonically equivalent

Enharmonic

In modern musical notation and tuning, an enharmonic equivalent is a note , interval , or key signature which is equivalent to some other note, interval, or key signature, but "spelled", or named, differently...

key.

Further reading