Editing Modulation (music) (section)

===Common-chord modulation <span class="anchor" id="Common-chord"></span><span class="anchor" id="Common chord"></span>===
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[[File:Chopin - Prelude in C minor opening modulation.png|thumb|350px|Common-chord modulation in the opening of [[Frédéric Chopin|Chopin's]] [[Preludes (Chopin)|Prelude in C minor]], Op. 28, No. 20.<ref>Benward and Saker (2009). ''Music in Theory and Practice'', Vol. II, p. 214. {{ISBN|978-0-07-310188-0}}.</ref>{{audio|Chopin - Prelude in C minor opening modulation.mid|Play}}]]
[[File:Common-chord modulation in Tchaikovsky, Mazurka Op. 39, No. 10.png|thumb|350px|Common-chord modulation in [[Pyotr Ilyich Tchaikovsky|Tchaikovsky]]'s ''Album pour enfants'' (1887), Op. 39, No. 10, ''Mazurka''<ref>Forte (1979), p. 307.</ref>{{audio|Common-chord modulation in Tchaikovsky, Mazurka Op. 39, No. 10.mid|Play}}]]
[[File:Common chord modulation in Mozart, Sonata in D Major, K. 284, III, m. 1-8.png|thumb|350px|Common-chord modulation in the opening of [[Wolfgang Amadeus Mozart|Mozart]]'s [[Piano Sonata No. 6 (Mozart)|Sonata in D Major, K. 284]], III<ref>Benward and Saker (2009), p. 244.</ref>{{audio|Common chord modulation in Mozart, Sonata in D Major, K. 284, III, m. 1-8.mid|Play}}]]

[[common-chord (music)|Common-chord]] modulation (also known as diatonic-pivot-chord modulation) moves from the original key to the destination key (usually a [[closely related key]]) by way of a chord both keys share: "Most modulations are made smoother by using one or more chords that are common to both keys."<ref>Forte (1979), p. 305.</ref> For example, G major and D major have four triad chords in common: G major, B minor, D major and E minor. This can be easily determined by a chart similar to the one below, which compares triad qualities. The I chord in G major—a G major chord—is also the IV chord in D major, so I in G major and IV in D major are aligned on the chart.

:{| class="wikitable" style="text-align:center"
|-
!G major
|bgcolor=#ffff99|I<br><small>G</small>
|ii<br><small>Am</small>
|bgcolor=#ffff99|iii<br><small>Bm</small>
|IV<br><small>C</small>
|bgcolor=#ffff99|V<br><small>D</small>
|bgcolor=#ffff99|vi<br><small>Em</small>
|vii{{music|dim}}<br><small>F{{music|#}}{{music|dim}}</small>
|-
!D major
|bgcolor=#ffff99|IV<br><small>G</small>
|V<br><small>A</small>
|bgcolor=#ffff99|vi<br><small>Bm</small>
|vii{{music|dim}}<br><small>C{{music|#}}{{music|dim}}</small>
|bgcolor=#ffff99|I<br><small>D</small>
|bgcolor=#ffff99|ii<br><small>Em</small>
|iii<br><small>F{{music|#}}m</small>
|}

Any chord with the same root note and chord quality (major, minor, diminished) can be used as the pivot chord. Therefore, chords that are not generally found in the style of the piece (for example, major VII chords in a [[J. S. Bach]]-style chorale) are also not likely to be chosen as the pivot chord. The most common pivot chords are the [[predominant chord]]s (ii and IV) in the new key. In analysis of a piece that uses this style of modulation, the common chord is labeled with its function in both the original and the destination keys, as it can be heard either way.

Where an [[altered chord]] is used as a pivot chord in either the old or new key (or both), this would be referred to as altered common chord modulation, in order to distinguish the [[chromaticism]] that would be introduced from the otherwise diatonic method.