The Solution below shows the B-flat major deceptive cadence on the piano and treble clef.
The Lesson steps then describe the cadence structure in this key, the chords used, followed by an example of its use.
For a quick summary of this topic, have a look at Cadence.
The deceptive deceptive cadence moves from the dominant (V), to a chord that is not the tonic(I) - eg. supertonic (ii) scale degree.
To demonstrate this, on the treble clef above, chords Bb major triad chord #I, Bb major triad chord #V, and Bb major triad chord #IV are used to set up the phrase as being in this key, then the cadence chords V and ii finish off the phrase, giving only a partial sense of completion, in comparison to the Bb major perfect authentic cadence
In music theory, a cadence is two chords which create a sense of closure, or rest to a phrase, section, or entire piece of music.
The most commonly used are: perfect authentic, imperfect authentic, plagal, deceptive and half cadence.
Some of the above are US-english terms. In the UK, authentic cadences are called perfect cadences, half cadences are called imperfect cadences, and deceptive cadences are called interrupted cadences.
Each of the above cadence types use different chords (or inversions) to create these rest / closure effects.
Strong cadences give a real sense of finality, and so are most often used right at the end of a piece.
In contrast, weak cadences are less conclusive, which can be used to create a sense of rest, or even surprise the listener with a false ending, when a strong cadence was expected in its place.
Before describing the details of the deceptive cadence in the key of B-flat major, first it would be to useful to identify the scale notes, degrees and chords that could be used in this key.
Below is a piano diagram showing the Bb major scale notes.
|Note no.||Note name||Scale degree||Triad chord #||7th chord #|
|1||Bb||tonic||Bb major triad chord #I||Bb major seventh chord #I7|
|2||C||supertonic||Bb major triad chord #ii||Bb major seventh chord #ii7|
|3||D||mediant||Bb major triad chord #iii||Bb major seventh chord #iii7|
|4||Eb||subdominant||Bb major triad chord #IV||Bb major seventh chord #IV7|
|5||F||dominant||Bb major triad chord #V||Bb major seventh chord #V7|
|6||G||submediant||Bb major triad chord #vi||Bb major seventh chord #vi7|
|7||A||leading tone||Bb major triad chord #viio||Bb major seventh chord #viiø7|
For each note in the scale (2nd column), there is a triad chord whose root / first note is that scale note (4th column), and the same applies to 7th chords (5th column).
According to the cadence type, some of these chords, scale degrees and roman numerals will be used in later steps to define this cadence.
The deceptive cadence moves from the dominant (V), to any other chord than I, eg. the supertonic (ii) scale degree.
It is less strong than the Bb major perfect authentic cadence because the dominant(V) and tonic(I) is the most fundamental diatonic scale degree relationship in western music.
The two chords above are shown as the last two chords on the treble clef below.
The first three chords on the staff below are not strictly part of the cadence, but they are useful to set the expectation that this phrase is definitely in the key of B-flat major.
To do this, we are using chords Bb major triad chord #I, Bb major triad chord #V, and Bb major triad chord #IV, and after hearing these chords, followed by the first chord in the cadence (chord V), our ear is definitely expecting tonic chord (I) as the final chord in the sequence.
Instead of resolving on the tonic chord, by resolving on the supertonic chord the sense of resolution and finality is not there, in comparison to the Bb major perfect authentic cadence.
The audio files below also contain all 5 chords shown on the treble clef above.