C6/9 Piano Chord - Charts, Harmony and Music Theory (2025)

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    Piano Diagram of C6/9in Root Position

    C6/9 Piano Chord - Charts, Harmony and Music Theory (1)

    C6/9 is a five-note chord consisting of the notes C, E, G, A, and D. It is a major chord with an added 6th and 9th. It belongs to the chord family of 6th chords, which are “Added chords”. Keep reading to gain a deeper understanding of the music theory behind this chord.

    Structure of C6/9

    Notes

    C, E, G, A, D

    Intervals

    R, 3, 5, 6, 9

    Playing Extended Chords on Piano

    Extended chords are an essential part of piano playing, providing a rich and complex sound. However, playing extended chords can be challenging due to the number of notes involved. One way to manage this is by omitting certain notes, such as the root or the 5th, or by dividing the chord between both hands.

    Despite these techniques, extended chords can still create dense harmonies that require careful voicing. When inverted, these chords can produce complex clusters of notes that need to be approached with skill and precision. Mastering the voicing of extended chords takes time and practice, but it’s a crucial skill for any pianist looking to expand their repertoire.

    C6/9 Chord Inversions

    The C6/9 chord has a total of 4 inversions:

    Root Position:CEGAD
    1st Inversion:EGACD
    2nd Inversion:GACDE
    3rd Inversion:ACDEG
    4th Inversion:DEGAC

    Piano Keyboard Diagrams

    C6/9 Piano Chord - Charts, Harmony and Music Theory (2)

    C6/9 Chord – Root Position

    C6/9 Piano Chord - Charts, Harmony and Music Theory (3)
    C6/9 Chord – 1st Inversion
    C6/9 Piano Chord - Charts, Harmony and Music Theory (4)
    C6/9 Chord – 2nd Inversion

    C6/9 Piano Chord - Charts, Harmony and Music Theory (5)
    C6/9 Chord – 3rd Inversion
    C6/9 Piano Chord - Charts, Harmony and Music Theory (6)
    C6/9 Chord – 4th Inversion

    Chord Inversion on Piano

    Chord inversions are a foundational concept in music theory, helping to explain how chords are built and how they fit into progressions. However, when we talk about chord inversions on a piano keyboard, it’s important to keep in mind that the diagrams we use to show the notes in an inversion might not always match up with practical playing.

    In practice, pianists use different voicings and fingerings for chords, spreading the notes out across different octaves and positions on the keyboard. This means that the basic shape of a chord’s inversions as shown in diagrams might not always be the most efficient way to play the chord on a piano keyboard.

    So while chord inversion diagrams can help understand the sequence of notes in a chord, they don’t always give us the best way to play the chord on a piano. It’s up to each pianist to experiment with different voicings and find the most comfortable and efficient way to play the chord while still maintaining the intended harmonic function and sound.

    Page Contents

    Music Theory and Harmony of C6/9

    Building the C6/9Chord: Different Approaches

    Starting from the C Major Scale

    To create a 6/9 chord, you can use the Major scale as a reference by combining a Root, a 3rd, a 5th, a 6th, and a 9th.

    In this case, to build a C6/9let’s start from the C Major scale:

    C6/9 Piano Chord - Charts, Harmony and Music Theory (7)

    C Major Scale

    Apply the formula R, 3, 5, 6, 9to get a C6/9 chord:

    1. Select the Root note, which is C.
    2. Pick the 3rd note, which is E, and add it to the chord.
    3. Add the 5th note, which is G, and include it as well.
    4. Now, add the 6th which is A.
    5. Lastly, include the 9th note of the C Major scale, which is a D.

    by Combining Intervals

    To build a 6/9 chord, one approach is to combine specific intervals, namely a major 3rd, a minor 3rd, a major 2nd (whole-tone), and a major 3rd.

    3 + m3 + 2 + 3 = 6/9 Chords

    When constructing a C6/9 chord, you can see that

    • C-E forms a major 3rd,
    • E-G creates a minor 3rd,
    • G-A makes a whole-tone interval, and
    • Bb-D is a major 3rd.

    Stacking these intervals together creates a C6/9 chord.

    How to Use C 6/9 in a Chord Progression

    Since 6/9th chords are based on major triads with a sixth and a ninth added, they can substitute the major chords built on the scale of the root. This means that we can use the C6/9 chord in those positions on the scale where the harmonization makes a major chord.

    In some cases, a 6/9 chord can be used as a dominant chord, but it is less common than its use as a tonic or subdominant chord.

    The following tables illustrate the harmonization of scales that contain a C Maj7 or a C7 chord.

    on Major Scales

    Major ScalesIiiiiiIVVvivii
    CC Maj7 ⇒ C6/9D min7E min7F Maj7G7A min7Bm7b5
    GG Maj7A min7B min7C Maj7 ⇒ C6/9D7E min7F#m7b5
    FF Maj7G min7A min7Bb Maj7C7 ⇒ C6/9D min7Em7b5
    • Tonic chord in C Major
    • Subdominant chord in G Major
    • Dominant chord in F Major (less common)

    on Natural minor Scales

    Minor ScalesiiiIIIivvVIVII
    AA min7Bm7b5C Maj7 ⇒ C6/9D min7E min7F Maj7G7
    EE min7F#m7b5G Maj7A min7B min7C Maj7 ⇒ C6/9D7
    DD min7Em7b5F Maj7G min7A min7Bb Maj7C7 ⇒ C6/9
    • Mediant chord in A minor
    • Submediant chord in E minor
    • Dominant chord in D minor (less common)

    C6/9 Chord Function in Major and Minor Keys

    Understanding Scale Degrees

    When we harmonize a scale, we use the notes of the scale to create chords. This means that the notes of the chords are all found within the scale itself.

    Each note in the scale is assigned a degree, which represents its position in the scale. The degrees of the harmonized diatonic major scale are as follows:

    1. Tonic (1st degree): serves as the tonal center or home base of the music and provides a sense of resolution and stability.
    2. Supertonic (2nd degree): often serves as a passing tone or a bridge between the tonic and other scale degrees.
    3. Mediant (3rd degree): helps to define the overall tonality of the scale (major or minor) and lies midway between the tonic and the dominant.
    4. Subdominant (4th degree): often used as a contrasting or complementary harmony to the dominant.
    5. Dominant (5th degree): creates tension and a sense of expectation, which is resolved when returning to the tonic.
    6. Submediant (6th degree): lies midway between the tonic and the subdominant and often serves as a bridge between the dominant and the tonic.
    7. Leading tone (7th degree): one half step below the tonic and creates a strong sense of tension and desire to resolve to the tonic.

    C6/9 in C Major

    C6/9 can be used instead of a C Maj or C Maj7 chord, which is the first chord in the harmonized C major scale.

    In a major key, the I chord (built on the first degree of the major scale) serves as the tonic chord, providing the harmonic center of the chord progression.

    IiiiiiIVVvivii
    C Maj7 ⇒ C6/9D min7E min7F Maj7G7A min7Bm7b5
    C6/9 Chord Progressions as I degree
    II V I
    iiVI
    D min7G7C6/9 | C Maj7
    I IV V
    IIVV
    C6/9F Maj7G7
    I V vi IV
    IVviIV
    C6/9G7A min7F Maj7

    C6/9 in G Major

    The C6/9 chord can also be used as the fourth degree of the G major scale as a substitute for the C Maj7. When applied to the I-IV-V progression, this chord on the fourth degree acts as a transitional chord between the first and fifth degrees.

    IiiiiiIVVvivii
    G Maj7A min7B min7C Maj7 ⇒ C6/9D7E min7F#m7b5
    C6/9 as IV degree – Chord Progressions

    Try playing these chord progressions to get an idea of how C6/9 functions as a substitute for the subdominant (IV degree) in a chord progression.

    I IV V
    IIVV
    G Maj7C6/9 | C Maj7D7
    I V vi IV
    IVviIV
    G Maj7D7E min7C6/9 | C Maj7
    I IV vi V
    IIVviV
    G Maj7C6/9 | C Maj7E min7D7

    C6/9 Chord in F Major

    Another (uncommon) way to use the C6/9 chord is as a substitution for the dominant chord in the F major scale. In this case, the C6/9 chord functions as a variation of the C7 chord, serving as the fifth degree of the F major scale.

    When used in a ii-V-I progression, the C6/9 chord on the fifth degree can function as the dominant chord that resolves to the first degree.

    IiiiiiIVVvivii
    F Maj7G min7A min7Bb Maj7C7 ⇒ C6/9D min7Em7b5
    C6/9 as V degree – Chord Progressions

    I prefer resolving the C6/9 chord to a C7 chord within the same measure, but I encourage you to explore different options and experiment with other chord progressions to see what sounds best to you.

    ii V I
    iiVI
    G min7C6/9 | C7F Maj7
    I IV vi V
    IIVviV
    F Maj7Bb Maj7D min 7C6/9 | C7
    I IV ii V iii vi ii V
    IIViiViiiviiiV
    F Maj7Bb Maj7G min7C6/9 | C7A min7D min7G min7C6/9 | C7

    C6/9 in A minor

    Similarly, in the key of A minor, the C6/9 chord can be used as a substitute for the C Maj7 chord as the third degree.

    iiiIIIivvVIVII
    A min7Bm7b5C Maj7 ⇒ C6/9D min7E min7F Maj7G7
    C6/9 as III degree – Chord Progressions

    These chord progressions show the C6/9 chord as a substitute for the mediant (III degree) chord.

    i III
    iIII
    A min7C6/9 | C Maj7
    i III VII VI
    iIIIVIIVI
    A min7C6/9 | C Maj7G7F Maj7
    Circle Progression
    iivVIIIIIVIiiV7i
    A min7D min7G7C6/9 | C Maj7F Maj7Bm7b5E7A min7

    C6/9 in E minor

    Another instance where you can use a C6/9 chord instead of a C Maj7 is while playing in the key of E. This is because the C Maj7 chord we are replacing is located on the sixth degree of the Eb-sharp minor scale.

    iiiIIIivvVIVII
    E min7F#m7b5G Maj7A min7B min7C Maj7 ⇒ C6/9D7
    C6/9 as VI degree – Chord Progressions

    Try playing these chord progressions to get a sense of how a C6/9 chord can serve as an alternative to a C Maj7 chord when it functions as the submediant (VI degree) in an E minor scale.

    i VI VII
    iVIVII
    E min7C6/9 | C Maj7D7
    i v VI VII
    ivVIVII
    E min7B min7C6/9 | C Maj7D7
    i III VII VI
    iIIIVIIVI
    E min7G Maj7D7C6/9 | C Maj7
    Circle Progression
    iivVIIIIIVIiiV7i
    E min7A min7D7G Maj7C6/9 | C Maj7F#m7b5B7E min7

    C6/9 in D minor

    Using a C6/9 instead of a Major or Major 7th as the dominant chord is not so common but it is worth mentioning.

    iiiIIIivvVIVII
    D min7Em7b5F Maj7G min7A min7Bb Maj7C7 ⇒ C6/9
    C6/9 as VII degree – Chord Progressions

    You can try playing these chord progressions to hear how the C6/9 chord works as a substitute for the subdominant (IV degree) or you can play it with the dominant 7th chord:

    i VI VII
    iVVII
    D min7Bb Maj7C6/9 | C7
    i v VI VII
    ivVIVII
    D min7A min7Bb Maj7C6/9 | C7
    i III VII VI
    iIIIVIIVI
    D min7F Maj7C6/9 | C7Bb Maj7
    Circle Progression
    iivVIIIIIVIiiV7i
    D min7G min7C6/9 | C7F Maj7Bb Maj7Em7b5A7D min7

    Alternative Names for C6/9

    • C6/9
    • C 6(9)
    • Do 6/9
    • C 6/9th
    • C add6/9

    Conclusion

    The chord progressions and examples presented in this post provide a comprehensive overview of the most common uses of the C6/9 chord. It’s important to note, however, that many advanced harmony-related topics could not be included due to space constraints. These topics include chord progressions built on harmonic and melodic scales, modal scales, hidden tonality, secondary dominants and other chord substitutions, non-functional harmony and atonal music, modal interchange and borrowed chords, voice leading and counterpoint, chromatisms, jazz harmony…I mean, music theory is a huge topic!

    Although I couldn’t cover all of these topics in my post, I encourage readers to continue exploring these areas in their study and research. By expanding your knowledge in these advanced areas of music theory, you can gain a deeper understanding of the harmonic possibilities that exist beyond the basics presented here.

    C6/9 Piano Chord - Charts, Harmony and Music Theory (2025)

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