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A leading-tone seventh is a seventh chord built on degree 7:
C major: B–D–F–A (viiø7, a half-diminished seventh) A minor: G♯–B–D–F (vii°7, a diminished seventh)
It has the same function as the dominant seventh: both are dominant-function chords resolving to the tonic. They differ in the bass: the dominant seventh has the dominant as its root, the leading-tone seventh has the leading tone.
Why it sounds sharper than a dominant seventh
Because the leading tone sits in the lowest voice. The bass is the most attended-to register (see chord voicing), so putting the least stable note there magnifies the tension.
| Chord | Bass | Impression |
|---|---|---|
| V7 | the dominant (stable) | forceful, but the bass itself is settled |
| vii°7 | the leading tone (a semitone below) | sharper, more "must resolve now" |
This also explains why composers favour it in minor: there the dominant needs a raised seventh to become a major triad (see harmonic minor), whereas the leading-tone seventh comes straight from the raised scale — stack thirds on the raised seventh and you have a diminished seventh chord.
The two forms
| Key | Chord | Seventh | Tritones |
|---|---|---|---|
| major | viiø7 | minor seventh | 1 |
| minor | vii°7 | diminished seventh | 2 |
The second row matters: in minor the leading-tone seventh is a diminished seventh, and two tritones make it the least settled of the common chords.
Substituting one for the other
Functionally they can replace each other, but not indifferently:
| Substitution | Effect |
|---|---|
| V7 → vii°7 | tension increases (the bass becomes the leading tone), and the bass rises a semitone into the tonic |
| vii°7 → V7 | tension eases, the bass settles, and the close feels firmer |
So the choice is really a choice about how sharp the ending should be.
Diagram: same function, different bass
Listen: leading-tone seventh against dominant seventh
Hear the dominant seventh (V7), then the leading-tone seventh (vii°7). Both resolve to the tonic, but the bass position makes them sound completely different.
Common misconceptions
- "Leading-tone and dominant sevenths are different functions." Same function: both are dominant-function chords resolving to the tonic. They differ in bass position and degree of tension.
- "In major, the leading-tone seventh is diminished." In a major key it is naturally half-diminished (viiø7). Getting a diminished seventh needs the fourth degree raised too (common in minor or in chromatic writing).
- "The leading-tone seventh is more advanced." Not more advanced — sharper. Choose it by the force you need, not by difficulty.
- "It belongs to minor keys only." It is just as common in major, merely as a half-diminished rather than diminished form.
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Listen in the library
All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).
Sources
- 导七和弦建立在音阶第 7 级；大调为半减七、小调（升 7 级）为减七，属和声学通则
- 导七与属七同属属功能，区别在低音位置（导音而非属音），为通行和声学表述
Used for fact-checking only; all prose is original.