The Solution below shows the C major plagal 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.

## Solution

### 1. C major plagal cadence

This step shows the plagal cadence in the key of C major.

The plagal cadence moves from the subdominant (IV), to the tonic (I) scale degree.

So in this major key, we are going from the C major triad chord #IV - F major chord, to C major triad chord #I - C major chord.

This is more commonly known as the Amen cadence, used at the end of many hymns.

To demonstrate this, on the treble clef above, chords C major triad chord #I and C major triad chord #V are used to set up the phrase as being in this key, then the cadence chords IV and I finish off the phrase, giving only a partial sense of completion, in comparison to the C major perfect authentic cadence.

## Lesson steps

This step describes the main cadence types, and the idea of strong versus weak 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.

#### Cadences - strong versus weak

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.

### 2. C major scale notes and chords

This step shows the C major scale notes and the triad chords in that scale.

Before describing the details of the plagal cadence in the key of C major, first it would be to useful to identify the scale notes, degrees and chords that could be used in this key.

#### C major scale notes

Below is a piano diagram showing the C major scale notes.

#### C major scale chords

For details on all the chords in this scale, have a look at C major triad chords, and C major 7th chords, but a summary table of all chord names and their scale degrees is shown below.

C major scale
Note no.Note nameScale degreeTriad chord #7th chord #
1CtonicC major triad chord #IC major seventh chord #I7
2DsupertonicC major triad chord #iiC major seventh chord #ii7
3EmediantC major triad chord #iiiC major seventh chord #iii7
4FsubdominantC major triad chord #IVC major seventh chord #IV7
5GdominantC major triad chord #VC major seventh chord #V7
6AsubmediantC major triad chord #viC major seventh chord #vi7

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).

To understand what the roman numerals mean, please look at C major triad chords or C major 7th chords.

According to the cadence type, some of these chords, scale degrees and roman numerals will be used in later steps to define this cadence.

### 3. C major plagal cadence

This step shows the C major plagal cadence on the piano and treble clef.

#### Structure

The plagal cadence moves from the subdominant (IV), to the tonic (I) scale degree.

So looking up the chords relating to these scale degrees from the table above, we are going from the C major triad chord #IV - F major chord, to C major triad chord #I - C major chord.

This is known as the Amen cadence because of its use in at the end of hymns.

It is a weaker closure than the C major perfect authentic cadence, whose dominant to tonic motion is the most important relationship in a diatonic scale, and gives the strongest sense of closure of all cadences.

#### Example

The two chords above are shown as the last two chords on the treble clef below.

The first two 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 C major.

To do this, we are using chords C major triad chord #I and C major triad chord #V, and after hearing these chords, the ear could expect to hear chord I again.

If instead the C major triad chord #IV is inserted before the final chord I, this gives less sense of closure and completion than arriving at chord I directly from chord V.

The audio files below also contain all 4 chords shown on the treble clef above.