Editing Leading tone (section)

== Leading-tone seventh chord ==
<!--[[Leading-tone seventh chord]] redirects and [[Template:Chords]] links directly here.-->{{anchor|Seventh chord}}
{{Image frame|content=<score sound="1" override_midi="Leading-tone seventh chords in Beethoven's no 5 op 10 no 1 I 13-16.mid">
   \new PianoStaff <<
      \new Staff <<
         \relative c'' {
             \set Score.currentBarNumber = #13
             \bar ""
             \clef treble \key c \minor \time 3/4
             \grace { g16_\markup { \italic "rinf." } c es } <g, g'>4.( <f f'>8) <es~ es'~>4(
             <es es'> <d d'>-.) <c~ c'~>->(
             <c c'> <b b'>-.) <aes~ aes'~>->(
             <aes aes'> <g g'>-.) r
             }
            >>
     \new Staff <<
         \relative c {
             \clef bass \key c \minor 
             \grace { s16 s s } r4 r <es g c>(
             <f aes b>2-> <es g>4 
             <d f>2 <c es>4 
             <b d>) r r
             }
         >>
    >>
</score>|width=425|caption=Leading-tone seventh chords (with [[suspension (music)|suspensions]]) functioning as dominant chords in Beethoven's [[Piano Sonata No. 5 (Beethoven)|Piano Sonata No. 5]], mvmt. I.{{sfn|Benward and Saker|2003|loc=217}}[[File:Leading-tone seventh chords in Beethoven's no 5 op 10 no 1 I 13-16.mid]]}}
The leading-tone seventh chords are vii{{music|halfdim}}<sup>7</sup> and vii{{music|dim}}<sup>7</sup>,{{sfn|Benward and Saker|2003|loc=218–219}} the [[half-diminished seventh chord|half-diminished]] and [[diminished seventh chord]]s on the seventh scale degree ({{music|scale|7}}) of the major and [[minor scale#Harmonic and melodic minor|harmonic minor]]. For example, in C major and C minor, the leading-tone seventh chords are B half-diminished (B–D–F–A) and B diminished (B–D–F–A{{music|b}}), respectively.

Leading-tone seventh chords were not characteristic of Renaissance music but are typical of the Baroque and Classical period. They are used more freely in Romantic music but began to be used less in classical music as conventions of tonality broke down. They are integral to ragtime and contemporary popular and jazz music genres.{{sfn|Benward and Saker|2003|loc=220–222}}

Composers throughout the [[common practice period]] often employed [[Borrowed chord|modal mixture]] when using the leading-tone seventh chord in a major key, allowing for the substitution of the half-diminished seventh chord with the fully diminished seventh chord (by lowering its seventh). This mixture is commonly used when the leading-tone seventh chord is functioning as a [[secondary leading-tone chord]].

The example below shows fully diminished seventh chords in the key of D major in the right hand in the third movement of [[Wolfgang Amadeus Mozart|Mozart]]'s [[Piano Sonata No. 5 (Mozart)|Piano Sonata No. 5]] in G major.{{sfn|Benward and Saker|2003|loc=218}}

:<score>
   \new PianoStaff <<
      \new Staff <<
         \relative c' {
             \clef treble \key g \major \time 3/8
             \set Score.currentBarNumber = #64
             \bar ""
             <e e'>8 e'16[ dis fis e]
             \once \override DynamicLineSpanner.staff-padding = #3.5 g16([\p e cis bes)] \once \override DynamicLineSpanner.staff-padding = #3.5  a8\f
             g'16([ e cis bes)] \once \override DynamicLineSpanner.staff-padding = #3.5  a8\f
             g'16([ e cis bes)] \once \override DynamicLineSpanner.staff-padding = #3.5  a8\f
             g'16([ e cis bes)] \once \override DynamicLineSpanner.staff-padding = #3.5 a8\f
             r r <d fis a>\f
             }
            >>
     \new Staff <<
         \new Voice \relative c' {
             \clef bass \key g \major \time 3/8
             R4. 
             r8 r \clef treble <cis e g>
             r8 r <cis e g>
             r8 r <cis e g>
             r8 r <cis e g>
             \clef bass \once \override DynamicLineSpanner.staff-padding = #3.5 d,16([^\p fis a d)] fis8
             }
         >>
    >>
</score>
:[[File:Leading-tone seventh chord as dominant in Mozart K 283 III mm 64-69.mid]]

=== Function ===
The leading-tone seventh chord has a [[dominant (music)|dominant]] [[diatonic function|function]] and may be used in place of V or V{{music|7 chord}}.{{sfn|Benjamin|Horvit|Nelson|2008|loc=128}} Just as vii{{music|dim}} is sometimes considered an incomplete dominant seventh chord, a leading-tone seventh chord is often considered a "[[dominant ninth chord]] without root".{{sfn|Gardner|1918|loc=49}}{{sfn|Goldman|1965|loc=72}})

: <score lang="lilypond">
{
\override Score.TimeSignature
#'stencil = ##f
\override Score.SpacingSpanner.strict-note-spacing = ##t
\set Score.proportionalNotationDuration = #(ly:make-moment 1/7)
\time 4/4 
\relative c'' { 
      <b d f aes>1^\markup { \column { "Leading-tone" "seventh chord" } }
   <g b d f aes>^\markup { \column { "Dominant minor" "ninth chord" } }
   }
}
</score>

For variety, leading-tone seventh chords are frequently [[chord substitution|substituted]] for [[dominant (music)|dominant chords]], with which they have three common tones:{{sfn|Benward and Saker|2003|loc=217}} "The seventh chord founded upon the subtonic [in major]... is occasionally used. It resolves directly to the tonic... This chord may be employed without preparation."{{sfn|Herbert|1897|loc=135}}

=== Voice leading ===
In contrast to leading-tone triads, leading-tone seventh chords appear in [[root position]]. The example below shows leading-tone seventh chords (in root position) functioning as dominants in a [[Reduction (music)|reduction]] of Mozart's ''[[Don Giovanni]]'', K. 527, act 1, scene 13.{{sfn|Benward and Saker|2003|loc=219}}

:<score sound="1">
{
      <<
        \new Staff <<
            \relative c' {
                \set Score.tempoHideNote = ##t \tempo 4 = 86
                \set Staff.midiInstrument = #"voice oohs"
                \clef treble \key b \minor \time 4/4
                \set Score.currentBarNumber = #116
                \bar ""
                   fis4 r r r8 g' fis b, r g' fis b, r f'
                }
                \addlyrics { troth! Re – mem – ber, when wound – ed, his }
            >>
      \new PianoStaff <<
        \new Staff <<
           \set Staff.midiInstrument = #"piano"
           \clef treble \key b \minor \time 4/4
           \relative c' {
                r16 <d fis> <d fis> <d fis> r <e g> <e g> <e g>
                r <d fis> <d fis> <d fis> r <e g> <e g> <e g>
                r <d fis> <d fis> <d fis> r <e g> <e g> <e g>
                r <d fis> <d fis> <d fis> r <d f> <d f> <d f>
                }
            >>
        \new Staff <<
           \clef bass \key b \minor \time 4/4
           \relative c' {
                b8 r <ais cis> r b r <ais cis> r
                b r <ais cis> r b r <gis b> r
                }
            >>
    >>  >> }
</score>

[[François-Joseph Fétis]] tunes the leading-tone seventh in major 5:6:7:9.{{sfn|Fétis|Arlin|1994|loc=139n9}}