• Tertian Chords and the Secret Relationship Between Almost Every Chord

    in Chords & Progressions,Theory

    tertian chords

    90% of all chords you’ll ever play are tertian chords.

    Tertian comes from the latin word “tertianus,” which means “of or concerning thirds.”

    THIRDS.

    Thirds control chords in music and if you’ve read my free “Complete Guide To Chords,” you know why.

    In short, if you look at the notes of the musical language as simple alphabet letters (that means, drop the sharps, drop the flats), you get:

    A B C D E F G

    Thirds are what result when you essentially skip every other alphabet letter.

    A B C D E F G A B C D E F G A B C D E F G A B C D E F G A

    Notice as we move in thirds (skipping every other note), we eventually cover all the letters of the musical alphabet.

    A C E G B D F

    In fact, think of ANY chord that does not use black keys and you’ll find it on this repeating list of thirds, as-is.

    Think of any chord that does have black keys and you’ll also find it on this repeating list of thirds (but you’ll have to add back in the appropriate sharps and flats for each chord).

    C major? C E G.

    I see it in there.

    A B C D E F G A B C D E F G A B C D E F G A B C D E F G A

    A minor? A C E.

    Yup.

    A B C D E F G A B C D E F G A B C D E F G A B C D E F G A

    B diminished? B D F.

    It’s there.

    A B C D E F G A B C D E F G A B C D E F G A B C D E F G A

    D minor? D F A.

    I see it.

    A B C D E F G A B C D E F G A B C D E F G A B C D E F G A

    F major? F A C.

    Yup yup.

    A B C D E F G A B C D E F G A B C D E F G A B C D E F G A

    G major? G B D.

    Yes.

    A B C D E F G A B C D E F G A B C D E F G A B C D E F G A

    E minor (E G B)? C major 7 (C E G B)? A minor 9 (A C E G B)? D minor 11 (D F A C E G)?

    Yup, everything is there.

    A B C D E F G A B C D E F G A B C D E F G A B C D E F G A

    A B C D E F G A B C D E F G A B C D E F G A B C D E F G A

    A B C D E F G A B C D E F G A B C D E F G A B C D E F G A

    A B C D E F G A B C D E F G A B C D E F G A B C D E F G A

    Ab major 7?

    Sure, it is! If you start with alphabet letters, you’ll find A C E G. Now, simply flat the appropriate tones and you get Ab C Eb G. There’s your Ab major 7.

    A B C D E F G A B C D E F G A B C D E F G A B C D E F G A

    (This is your starting point. Your Ab major 7 chord will never have any letters other than A, C, E, or G). When you apply further chord rules, you get Ab + C + Eb + G, or Ab major 7.)

    Tertian Chords – The Stuff Chords Are Made Of!

    95% of chords are made up of small third intervals and thus found on this list by skipping every other note.

    If we convert this list to start with C, it looks like this:

    C D E F G A B C D E F G A B C D E F G A B C D E F G A B C

    It would behoove you to learn this order of notes:

    C E G B D F A C E G B D F A

    *I’ve repeated it here twice. You only need to learn the order of the first 7 letters.

    (I wish I could come up with some cool saying like I did to describe the whole step / half step process for learning major scales – “Why Won’t He Wear White When Hot”… but the idea is still incubating.) :-)

    Update: One of our dedicated students, Kathy Braun, submitted these acronyms for memorizing “C E G B D F A”:

    • Creative Excellence Gets Born During Forward Action
    • Caldonia Enjoys Grapes But Delores Favors Apples

    Can you think of any?

    Here are some insights/observations to draw from the order of these notes:

    -This is a big web. C major 9 (C E G B D) has E minor 7 (E G B D) inside of it, which has G major (G B D) inside of it.

    -All triads use the first 3 letters (no matter where you start… C E G, D F A, B D F). Just know which letters to sharp (raise) and flat (lower). That means, no matter what B chord you want to play, it will always have the letters B D F.

    If you’re playing B major, it’s going to be B D# F# but it will never use any other letters.

    If you want to play B minor, the same rule is true. It must use a B, D, and F. In this case, B D F#.

    B diminished? B D F.

    B Augmented? B D# F## (not G!).

    -All sevenths use the first 4 letters (no matter where you start).

    C E G B = C major 7.
    C Eb G Bb = C minor 7.
    C E G Bb = C dominant 7.
    C Eb Gb Bbb = C diminished 7.

    All 7th chords having to do with “C” will always use C, E, G, and B.

    …Because they’re “tertian chords.”

    -All ninth chords use the first 5 letters (no matter where you start).

    C E G B D.
    A C E G B.
    E G B D F.

    All of these represent some type of ninth chord (whether major 9, minor 9, or even an altered 9th chord).

    -Elevenths = 6 letters.

    Thirteenths = All 7 (just beginning at a different point with various notes raised and/or lowered).

    -Altered chords follow these rules too.

    C dominant 7 #9#5?

    It will not use any letters outside of C, E, G, B, D. We just have to take certain tones and raise and/or lower them accordingly.

    Since this is a dominant chord, we lower B to Bb.

    C E G Bb.

    Since this is a chord with a sharp 9, we raise the D to D# (notice I didn’t call it Eb).

    And since this chord has a sharp 5, we also raise the G to G#. That leaves us with C E G# Bb D#.

    Yes, you can mix sharps and flats. In fact, you MUST mix sharps and flats in order to keep the letters C E G B D. Using A extends the chord to 6 letters, which makes it a 13th (hope that makes sense).

    There you have it…

    The secret relationship between all chords.

    See ya next time.

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    Hi, I'm Jermaine Griggs, founder of this site. We teach people how to express themselves through the language of music. Just as you talk and listen freely, music can be enjoyed and played in the same way... if you know the rules of the "language!" I started this site at 17 years old in August 2000 and more than a decade later, we've helped literally millions of musicians along the way. Enjoy!




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